VOLDEV-50 Activate buttons after changing badge

Reenable the input elements after changing/reverting a badge on Special:AchievementsCustomize + assorted code linting
VOLDEV-50: Code review changes
Merge pull request #3386 from WikiaVolDev/VOLDEV-50

VOLDEV-50 | Achievements: 'Revert to default' option should re-enable Browse and Save buttons