cmake/clang_tidy.cmake: fixed header-filter and added new warning-blacklists required by the new header-filter

cmake/clang_tidy.cmake: disabled (misc|cppcoreguidelines)-non-private-member-variables-in-classes warning

cmake/gtest.cmake: changed target from gmock_main to GTest.gmock_main and changed to use find_package

furhtermore, several other improvements were done:
- added new compiler warnings for gcc-10 and gcc-11 for pedantic builds
- created new build-targets (i.e. libClaPP_CXX_COMPILE_OPTIONS) which contain
  all warnings for the current compiler.

- bump version to 0.2.0
- updated README.md
- added and updated several tests
- added and updated doc
- updated sample_extractor and added sample_executor
- added clang-format specification
- added support for sanitizers
- added more exhaustive gitlab-pipeline
- added more specific exceptions
- updated help-message generation in parsers (sub_parser, main_parser and basic_parser)
- minor improvements of CMakeLists.txt (e.g. added cppcheck)
- renamed full_example to large_example
- minor improvements to examples
- added test examples scripts
- added build_info_string
- unified arguments and options