Expose Api version through PluginInfo

Authored by QChris on May 31 2020, 7:42 AM.


Expose Api version through PluginInfo

By adding Api version to PluginInfo, it becomes easier to check if all
plugins of a Gerrit server got built for the correct Api. This is
especially useful when upgrading servers.

This commit only exposes the Api version through the Api. Showing it in
the default output of the corresponding Ssh list command or in the UI
will happen in follow-up commits.

Change-Id: Id0c459dd104b4582fde1846e7710d6ad0ffc2f93