Add mutation testing support and CI/CD workflow

[lotyp]

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 23.34%. Comparing base (af9ad19) to head (45fc92d). Report is 51 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##             master     #110   +/-   ##
=========================================
  Coverage     23.34%   23.34%           
  Complexity     1232     1232           
=========================================
  Files           146      146           
  Lines          3834     3834           
=========================================
  Hits            895      895           
  Misses         2939     2939           

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[lotyp]

Looks like we currently have problem, where pest is blocking phpunit to run. I had this issue on other project, there should be solution.

One problem could be because of src/Tests/Proto, to resolve, we should disable some tests, and check, which suite/group breaks pest and phpunit.

[roxblnfk]

Need to limit phpunit using testsuite Unit

[lotyp]

@roxblnfk I've created issue, as, probably, there is bug in upstream package vimeo/psalm: https://github.com/vimeo/psalm/issues/11006