[feature/revisions] Replace "return to" with breadcrumbs

PHPBB3-10755
[feature/revisions] Display revision array position instead of id

PHPBB3-10755
[feature/revisions] Fix title of icons

PHPBB3-10755
[feature/revisions] Fix test request URL

PHPBB3-10755
[feature/revisions] Add avatars back to the comparison list.

PHPBB3-10755
[feature/revisions] Add some space below the success message and remove bolding

PHPBB3-10755