Clarify code: remove commented out code, update comments, rename files

.gitlab-ci.yml

cpp/msv3readutils.cc

cpp/oskar/oskarelementresponse.cc

cpp/telescope/oskar.cc

demo/comparison-oskar/CMakeLists.txt

demo/comparison-oskar/compare_stationresponse.py

demo/comparison-oskar/generate_basefunction_plots.py

demo/comparison-oskar/make_element_response_image.cpp

demo/comparison-oskar/make_station_response_image.cpp

demo/comparison-oskar/read_oskar_beams.py

demo/comparison-oskar/skalowmini-coef.tm/README.md