Deprecate `runas` usage on `salt.states.supervisord`. Refs #6961.

Additionally, on `mod_watch`, switched `restart` from `False` to `True` since that was what was being done before switching to explicit keyword arguments when calling `running`.
Deprecate `runas` usage on `salt.states.rvm`. Refs #6961.
Deprecate `runas` usage on `salt.states.rbenv`. Refs #6961.
Include `user` and deprecate `runas` on doctrings for `salt.states.supervisord`. Refs #6961.
Include `user` and deprecate `runas` on doctrings for `salt.states.rvm`. Refs #6961.
Deprecate `user` usage on `salt.states.rabbitmq_vhost` in favor of `owner`. Refs #6961.
Deprecate `runas` usage on `salt.states.postgres_user`. Refs #6961.
Fix doctrings and warn message for `salt.states.rvm`. Refs #6961.
Fix doctrings and warn message for `salt.states.supervisord`. Refs #6961.
Fix doctrings and warn message for `salt.states.rbenv`. Refs #6961.