Fix calendar delete wording

[raimund-schluessler]

• Don't show calendar delete option if the calendar is read-only (e.g. a list from Deck)
• Call calendars that don't support tasks "lists" to prevent confusion

Closes #1279.

[codecov]

Codecov Report

Merging #1290 into master will decrease coverage by 0.10%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master    #1290      +/-   ##
==========================================
- Coverage   27.67%   27.56%   -0.11%     
==========================================
  Files          47       47              
  Lines        2656     2666      +10     
  Branches      505      514       +9     
==========================================
  Hits          735      735              
- Misses       1779     1789      +10     
  Partials      142      142              

[raimund-schluessler]

I will wait for a couple of days before releasing a new version to let the translations being updated.