[DONE] More 3.5.1 fixes

[Badatos]

• Correct the Februray 29th bug (cannot add years to the 29/02) : use timedelta instead of just changing year value
• Correct bug on video playback with marker, causing anonymous audio files cannot be played anymore
• Add missing btn-link class on dressing button for keyboard focus
• Improve A11y of token table and bulk list view
• Correct some i18n strings
• Code formatting
• improve bulk update list CSS
• now BS tooltips are also applied on infinite scroll items

[Badatos]

Changements apportés. Merci @AymericJak ;)