[ticket/12251] Sort IM profile fields alphabetically

PHPBB3-12251
[ticket/12251] Deactivate outdated profile fields by default

PHPBB3-12251
[ticket/12251] Enable displaying profile fields on memberlist, posts and pms

PHPBB3-12251
[ticket/12251] Load profile fields by default on posts, pms and memberlist

PHPBB3-12251
[ticket/12251] Add string validation for a-zA-Z0-9 and underscore

PHPBB3-12251
[ticket/12251] Remove leading whitespace on doc blocks

PHPBB3-12251
Merge pull request #2089 from nickvergessen/ticket/12251

[ticket/12251] Clean up and Enhancement of Custom Profile Fields