Enhance error handling

assigned to @roman.azarenko

I would suggest adding rules to run_static_code_analysis and run_shell_check jobs to avoid spawning jobs in the first place if their respective source code path var is undefined or set to SKIP.

Otherwise you'll have green/passed jobs that give a false impression that the code passes those checks, unless one explicitly checks the logs. Also unnecessarily spawns extra jobs that don't bring any value.

Please split out commenting out run_cppcheck_clang_validation into a separate commit, as it seems to be a logically separate change.