Move to typed properties and IInitialState

[tcitworld]

And a few extras

Needs https://github.com/nextcloud/calendar/pull/4279

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 22.87%. Comparing base (aadc104) to head (b211fc7). Report is 10 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #4282      +/-   ##
============================================
- Coverage     23.31%   22.87%   -0.44%     
  Complexity      442      442              
============================================
  Files           247      247              
  Lines         11444    11369      -75     
  Branches       1923     1923              
============================================
- Hits           2668     2601      -67     
+ Misses         8776     8768       -8     

Flag	Coverage Δ
javascript	14.59% <ø> (ø)
php	58.39% <ø> (-1.05%)	:arrow_down:

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[ChristophWurst]

conflicts mildly

[miaulalala]

I need https://github.com/nextcloud/calendar/pull/5881 and https://github.com/nextcloud/calendar/pull/5882 to be sure everything's allright.

[miaulalala]