[ticket/13024] Add template event viewtopic_body_postrow_post_content_footer

PHPBB3-13024
Merge pull request #2913 from Nicofuma/ticket/13024

[ticket/13024] Add template event viewtopic_body_postrow_post_content_footer
Merge branch 'develop-ascraeus' into develop

Conflicts:
	phpBB/styles/subsilver2/template/viewtopic_body.html
[ticket/13024] Fix event file (remove subsilver references)

PHPBB3-13024