Set address space limit in systemd service file
We have a bootstrap check for the maximum size of the virtual memory
address space for the Elasticsearch process. We can set this in the
service file for Elasticsearch when installed as a service on
systemd-based systems for a better user experience than them fumbling
through thinking they should set this via /etc/security/limits.d (as a
lot of pages on the Internet would tell them) not realizing that systemd
completely ignores these for services and then trying to figure out how
to add a unit file for the Elasticsearch service.
Relates #25975