Improve umbrella header generation

[ntadej]

Improve umbrella header generation so they are not re-created on each CMake run.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (3b0db29) 36.20% compared to head (cfd35ca) 36.20%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #64   +/-   ##
=======================================
  Coverage   36.20%   36.20%           
=======================================
  Files          25       25           
  Lines        1820     1820           
=======================================
  Hits          659      659           
  Misses       1161     1161           

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[louwers]

What is the umbrella header in this context?

[ntadej]

Qt has it common that for one library you import everything at once. So we have QMapLibre header which just includes all other public headers. Here we try to make the library behave similar to Qt so users can use it in the same fashion.

For now the header is not fully generated yet, but this is a first step towards it.