[ticket/13026] Add template vars array to core.viewonline_overwrite_location

Add template vars array to core.viewonline_overwrite_location event
to allow modifying/adding template vars for every user row.

PHPBB3-13026
Merge pull request #2911 from rxu/ticket/13020

[ticket/13020] Add variables to core.viewforum_get_topic_data event
Merge branch 'develop-ascraeus' into develop
Merge pull request #2915 from rxu/ticket/13026

[ticket/13026] Add template vars array to core.viewonline_overwrite_location
Merge branch 'develop-ascraeus' into develop