Add clang-tidy checks and improve memory usage

[ntadej]

This MR improves memory handling validated by clang-tidy.

For clang-tidy the highest possible number of checks is added that makes sense (meaning not requiring large refactoring). Still there were many tiny changes needed.

Style handling refactoring will be done in a separate PR.

[codecov]

Codecov Report

Attention: 211 lines in your changes are missing coverage. Please review.

Comparison is base (75366ce) 36.20% compared to head (922c7bc) 35.88%.

Files	Patch %	Lines
src/core/map.cpp	22.32%	87 Missing ⚠️
src/location/stylechange.cpp	0.00%	39 Missing ⚠️
src/core/conversion_p.hpp	0.00%	17 Missing ⚠️
src/location/qgeomap.cpp	63.15%	14 Missing ⚠️
src/core/geojson.cpp	0.00%	11 Missing ⚠️
src/core/types.hpp	21.42%	11 Missing ⚠️
src/core/settings.cpp	62.50%	9 Missing ⚠️
src/widgets/gl_widget.cpp	43.75%	9 Missing ⚠️
src/core/scheduler.cpp	0.00%	5 Missing ⚠️
src/location/qt_mapping_engine.cpp	82.60%	4 Missing ⚠️
... and 3 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #65      +/-   ##
==========================================
- Coverage   36.20%   35.88%   -0.32%     
==========================================
  Files          25       25              
  Lines        1820     1839      +19     
==========================================
+ Hits          659      660       +1     
- Misses       1161     1179      +18     

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