- Updated mail notification design to be a bit prettier, and extracted
text to new lang file for translation.
- Added debounce logic for page update notifications.
- Fixed watch options not being filtered to current user.
- Adds option filtering and alternative text for page watch options.
- Adds "Watched & Ignored Items" list to user notification preferences
page to show existing watched items.
Kept existing "COMMENTED_ON" activity for upgrade compatibility,
specifically for existing webhook usage and for showing comment
activities in activity lists.
Precursor to content notifications.
Currently untested.
Also applied some type updates.
