Add CI pipeline with mutation testing

[roxblnfk]

Integrate infection with stryker

[lotyp]

I will take this issue.

[lotyp]

Mutation testing job example can be found here:

https://github.com/wayofdev/php-cs-fixer-config/blob/master/.github/workflows/testing.yml

README.md badges will be added by completing this task: #109

[lotyp]

PR: #110