[API] bulk request now supports timeout, see #4220

rest-api-spec/api/bulk.json

@@ -34,6 +34,10 @@
         "type": {
           "type" : "string",
           "description" : "Default document type for items which don't provide one"
+        },
+        "timeout": {
+          "type" : "time",
+          "description" : "Explicit operation timeout"
         }
       }
     },