Add offline install instructions for plugins

Follow up of https://github.com/elastic/elasticsearch/issues/15925#issuecomment-171250150

This commit adds offline install instructions for plugins.

docs/plugins/analysis-icu.asciidoc

@@ -21,6 +21,9 @@ sudo bin/elasticsearch-plugin install analysis-icu
 The plugin must be installed on every node in the cluster, and each node must
 be restarted after installation.
 
+This plugin can be downloaded for offline install from
+{plugin_url}/analysis-icu/{version}/analysis-icu-{version}.zip[elastic download service].
+
 [[analysis-icu-remove]]
 [float]
 ==== Removal

docs/plugins/analysis-kuromoji.asciidoc

@@ -18,6 +18,9 @@ sudo bin/elasticsearch-plugin install analysis-kuromoji
 The plugin must be installed on every node in the cluster, and each node must
 be restarted after installation.
 
+This plugin can be downloaded for offline install from
+{plugin_url}/analysis-kuromoji/{version}/analysis-kuromoji-{version}.zip[elastic download service].
+
 [[analysis-kuromoji-remove]]
 [float]
 ==== Removal

docs/plugins/analysis-phonetic.asciidoc

@@ -19,6 +19,9 @@ sudo bin/elasticsearch-plugin install analysis-phonetic
 The plugin must be installed on every node in the cluster, and each node must
 be restarted after installation.
 
+This plugin can be downloaded for offline install from
+{plugin_url}/analysis-phonetic/{version}/analysis-phonetic-{version}.zip[elastic download service].
+
 [[analysis-phonetic-remove]]
 [float]
 ==== Removal

docs/plugins/analysis-smartcn.asciidoc

@@ -24,6 +24,9 @@ sudo bin/elasticsearch-plugin install analysis-smartcn
 The plugin must be installed on every node in the cluster, and each node must
 be restarted after installation.
 
+This plugin can be downloaded for offline install from
+{plugin_url}/analysis-smartcn/{version}/analysis-smartcn-{version}.zip[elastic download service].
+
 [[analysis-smartcn-remove]]
 [float]
 ==== Removal

docs/plugins/analysis-stempel.asciidoc

@@ -21,6 +21,9 @@ sudo bin/elasticsearch-plugin install analysis-stempel
 The plugin must be installed on every node in the cluster, and each node must
 be restarted after installation.
 
+This plugin can be downloaded for offline install from
+{plugin_url}/analysis-stempel/{version}/analysis-stempel-{version}.zip[elastic download service].
+
 [[analysis-stempel-remove]]
 [float]
 ==== Removal

docs/plugins/discovery-azure-classic.asciidoc

@@ -21,6 +21,9 @@ sudo bin/elasticsearch-plugin install discovery-azure-classic
 The plugin must be installed on every node in the cluster, and each node must
 be restarted after installation.
 
+This plugin can be downloaded for offline install from
+{plugin_url}/discovery-azure-classic/{version}/discovery-azure-classic-{version}.zip[elastic download service].
+
 [[discovery-azure-classic-remove]]
 [float]
 ==== Removal

docs/plugins/discovery-ec2.asciidoc

@@ -19,6 +19,9 @@ sudo bin/elasticsearch-plugin install discovery-ec2
 The plugin must be installed on every node in the cluster, and each node must
 be restarted after installation.
 
+This plugin can be downloaded for offline install from
+{plugin_url}/discovery-ec2/{version}/discovery-ec2-{version}.zip[elastic download service].
+
 [[discovery-ec2-remove]]
 [float]
 ==== Removal

docs/plugins/discovery-gce.asciidoc

@@ -17,6 +17,9 @@ sudo bin/elasticsearch-plugin install discovery-gce
 The plugin must be installed on every node in the cluster, and each node must
 be restarted after installation.
 
+This plugin can be downloaded for offline install from
+{plugin_url}/discovery-gce/{version}/discovery-gce-{version}.zip[elastic download service].
+
 [[discovery-gce-remove]]
 [float]
 ==== Removal

docs/plugins/index.asciidoc

@@ -4,6 +4,7 @@
 :guide:          https://www.elastic.co/guide
 :version:        6.0.0-alpha1
 :lucene_version: 6.2.0
+:plugin_url:     https://download.elastic.co/elasticsearch/release/org/elasticsearch/plugin
 
 [[intro]]
 == Introduction to plugins

docs/plugins/ingest-attachment.asciidoc

@@ -25,6 +25,9 @@ sudo bin/elasticsearch-plugin install ingest-attachment
 The plugin must be installed on every node in the cluster, and each node must
 be restarted after installation.
 
+This plugin can be downloaded for offline install from
+{plugin_url}/ingest-attachment/{version}/ingest-attachment-{version}.zip[elastic download service].
+
 [[ingest-attachment-remove]]
 [float]
 ==== Removal

docs/plugins/ingest-geoip.asciidoc

@@ -25,6 +25,9 @@ sudo bin/elasticsearch-plugin install ingest-geoip
 The plugin must be installed on every node in the cluster, and each node must
 be restarted after installation.
 
+This plugin can be downloaded for offline install from
+{plugin_url}/ingest-geoip/{version}/ingest-geoip-{version}.zip[elastic download service].
+
 [[ingest-geoip-remove]]
 [float]
 ==== Removal

docs/plugins/ingest-user-agent.asciidoc

@@ -20,6 +20,9 @@ sudo bin/elasticsearch-plugin install ingest-user-agent
 The plugin must be installed on every node in the cluster, and each node must
 be restarted after installation.
 
+This plugin can be downloaded for offline install from
+{plugin_url}/ingest-user-agent/{version}/ingest-user-agent-{version}.zip[elastic download service].
+
 [[ingest-user-agent-remove]]
 [float]
 ==== Removal

docs/plugins/lang-javascript.asciidoc

@@ -21,6 +21,9 @@ sudo bin/elasticsearch-plugin install lang-javascript
 The plugin must be installed on every node in the cluster, and each node must
 be restarted after installation.
 
+This plugin can be downloaded for offline install from
+{plugin_url}/lang-javascript/{version}/lang-javascript-{version}.zip[elastic download service].
+
 [[lang-javascript-remove]]
 [float]
 ==== Removal

docs/plugins/lang-python.asciidoc

@@ -20,6 +20,9 @@ sudo bin/elasticsearch-plugin install lang-python
 The plugin must be installed on every node in the cluster, and each node must
 be restarted after installation.
 
+This plugin can be downloaded for offline install from
+{plugin_url}/lang-python/{version}/lang-python-{version}.zip[elastic download service].
+
 [[lang-python-remove]]
 [float]
 ==== Removal

docs/plugins/mapper-attachments.asciidoc

@@ -23,6 +23,9 @@ sudo bin/elasticsearch-plugin install mapper-attachments
 The plugin must be installed on every node in the cluster, and each node must
 be restarted after installation.
 
+This plugin can be downloaded for offline install from
+{plugin_url}/mapper-attachments/{version}/mapper-attachments-{version}.zip[elastic download service].
+
 [[mapper-attachments-remove]]
 [float]
 ==== Removal

docs/plugins/mapper-murmur3.asciidoc

@@ -19,6 +19,9 @@ sudo bin/elasticsearch-plugin install mapper-murmur3
 The plugin must be installed on every node in the cluster, and each node must
 be restarted after installation.
 
+This plugin can be downloaded for offline install from
+{plugin_url}/mapper-murmur3/{version}/mapper-murmur3-{version}.zip[elastic download service].
+
 [[mapper-murmur3-remove]]
 [float]
 ==== Removal

docs/plugins/mapper-size.asciidoc

@@ -19,6 +19,9 @@ sudo bin/elasticsearch-plugin install mapper-size
 The plugin must be installed on every node in the cluster, and each node must
 be restarted after installation.
 
+This plugin can be downloaded for offline install from
+{plugin_url}/mapper-size/{version}/mapper-size-{version}.zip[elastic download service].
+
 [[mapper-size-remove]]
 [float]
 ==== Removal

docs/plugins/repository-azure.asciidoc

@@ -18,6 +18,9 @@ sudo bin/elasticsearch-plugin install repository-azure
 The plugin must be installed on every node in the cluster, and each node must
 be restarted after installation.
 
+This plugin can be downloaded for offline install from
+{plugin_url}/repository-azure/{version}/repository-azure-{version}.zip[elastic download service].
+
 [[repository-azure-remove]]
 [float]
 ==== Removal

docs/plugins/repository-gcs.asciidoc

@@ -20,6 +20,9 @@ NOTE: The plugin requires new permission to be installed in order to work
 The plugin must be installed on every node in the cluster, and each node must
 be restarted after installation.
 
+This plugin can be downloaded for offline install from
+{plugin_url}/repository-gcs/{version}/repository-gcs-{version}.zip[elastic download service].
+
 [[repository-gcs-remove]]
 [float]
 ==== Removal

docs/plugins/repository-hdfs.asciidoc

@@ -18,6 +18,9 @@ sudo bin/elasticsearch-plugin install repository-hdfs
 The plugin must be installed on _every_ node in the cluster, and each node must
 be restarted after installation.
 
+This plugin can be downloaded for offline install from
+{plugin_url}/repository-hdfs/{version}/repository-hdfs-{version}.zip[elastic download service].
+
 [[repository-hdfs-remove]]
 [float]
 ==== Removal

docs/plugins/repository-s3.asciidoc

@@ -20,6 +20,9 @@ sudo bin/elasticsearch-plugin install repository-s3
 The plugin must be installed on every node in the cluster, and each node must
 be restarted after installation.
 
+This plugin can be downloaded for offline install from
+{plugin_url}/repository-s3/{version}/repository-s3-{version}.zip[elastic download service].
+
 [[repository-s3-remove]]
 [float]
 ==== Removal

docs/plugins/store-smb.asciidoc

@@ -17,6 +17,9 @@ sudo bin/elasticsearch-plugin install store-smb
 The plugin must be installed on every node in the cluster, and each node must
 be restarted after installation.
 
+This plugin can be downloaded for offline install from
+{plugin_url}/store-smb/{version}/store-smb-{version}.zip[elastic download service].
+
 [[store-smb-remove]]
 [float]
 ==== Removal