MOCCACAL-24: Use FullCalendar app as dependency

- fix bad typo that caused search to return empty results very often
MOCCACAL-24: Use FullCalendar app as dependency

- updating events now work again
- update the plainAgenda view to use the new fullCalendar View
- some more cleanup, especially avoid using global variables
  and put back a few i18n keys that have gone missing