Remove R example

[timmens]

Changes

• Remove R example tasks
• Remove R dependencies
• Remove R from documentation

Todo

• Reference issues which can be closed due to this PR with "Closes #x".
• Review whether the documentation needs to be updated.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (f1cbaaa) to head (4185e0c).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #172   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           10        10           
  Lines          131       116   -15     
=========================================
- Hits           131       116   -15     

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[hmgaudecker]

Very nice, thanks! I just made a couple of bigger changes to the language in the docs / README. Could you double-check those, please?