* updated workflows to `jurplel/install-qt-action@v3`
* release-windows.yml: removed installation of unavailable `qthelp` module
* release-windows.yml: do not hard-code `tools_openssl_x64` version
* Makefile: bail out if `pcre-config` is missing
* CI-unixish.yml: install `pcre` for `macos` via `brew` since it suddenly disappeared from the runner images
* added/updated to Python 3.11 in CI
* specify `check-latest: true` for `actions/setup-python` so we always use the latest version
* scriptcheck.yml: added note about `shellcheck`
* CI-unixish.yml: handle precompiled headers with `ccache`
* actually support `ccache` in CMake < 3.17
* CI-unixish-docker.yml: split CMake build and test execution into separate steps
* findDependencies.cmake: only print message about macthcompiler being disabled when it is actually used
* CI-unixish-docker.yml: added missing `ccache` CMake options
* iwyu.yml: use debian:unstable to always get latest include-what-you-use
* cleaned up includes based on include-what-you-use
* mitigated include-what-you-use false positives
* cleaned up triage.pro and pass all triage files to selfcheck
* CI-unixish.yml: factored out redundant selfcheck flags
* CI-unixish.yml: cleaned up selfcheck suppressions and fixed warnings
* added explicit `missingInclude` checks to selfcheck to work around current issues/limitations / fixed selfcheck includes / added some unit tests for `missingInclude`
* applied the selfcheck changes to the sanitizer jobs
* only fail TSAN CI build in case of TSAN error / updated sanitizer CI build TODOs
* lib/CMakeLists.txt: removed unnecessary external include
* look up tinyxml2 include dir when using system one and specify it
* lib/CMakeLists.txt: do not treat bundled headers as system ones
* CI-unixish.yml: actually perform system tinyxml2 build on macos
* modernized some CMake invocations
* CI-unixish.yml: use `ccache` for Linux gcc CMake builds
* CI-unixish-docker.yml: use `ccache` for Linux gcc CMake builds
* CI-unixish-docker.yml: enabled CMake build with tests for more images
* CI-unixish-docker.yml: adjusted some step checks
* coverage.yml: avoid duplicated test execution
* coverage.yml: split test execution and report generation into separate steps
* coverage.yml: split software and Python package installation into separate steps
* coverage.yml: removed unnecessary `libcppunit-dev` installation - library headers are only needed when performing syntax checking