Enhance phpBB profile fields with character info (from pbwowext#10, part 2) #368

Part 2 of restoring the removed pbwowext feature (avatharbe/pbwowext#10).

Enhance phpBB custom profile fields with character info for a user's linked character: class, race, level, active spec, faction-based styling, armory link. Reuses the character data already synced by bbguildwow (2.1.0). Companion to #231 (roster integration with custom profile fields & UCP).

Component: bbguildwow (+ core hooks). Ref: avatharbe/pbwowext#10.
Part 1 (character-based forum avatars) is tracked separately in 2.1.0 — see #369.