added publicholiday getter for whole year to JollydayCalendar/CalendarController

refs #14788
added new custom calendar (only overview)

* added momentjs for easier date handling

calendar:
* days can be selected with mouseclick, mousedown & move
* animation when changing visible months

removed jquery ui datepicker as strange behaviour occurred while
rerendering it. (functions where called twice with the same date but
other timezone, etc...)

refs #14788
calendar style adjustments

refs #14788
calendar is not rendered until scripts/holidays are loaded

refs #14788
days can only be selected with left click now

refs #14788
booking holiday in overview is triggered on click now

instead of mousedown

refs #14788
calendar/view/holidayService must be created now and urlPrefix is injected

refs #14788
fixed fallback for adding scripts

original deferred must be resolved of course if fallback script is
loaded...
calendar style improvements
added first example for calendar half workday/holiday
added todos to calendarjs
booked holidays are displayed in overview calendar now

refs #14788
clicking selected days in overview calendar redirects to application/new now

refs #14788
Show project version in header on login page.

* refs #16060
Remove row 'average duration of disease' from sick note statistics.

* refs #15964
Add + integrate year selector tag.

* refs #15963
Unify of selector's css classes.

* refs #15963
Integrate edit button in person overview header.

* refs #15963
Adjust new overview calendar.

* Number of displayed months is now not fixed but depends on screen
  width.
* Only allowed applications are highlighted in the overview calendar.

* refs #14788
Merge branch 'improved_calendar'