Setup GitLab CI pipelines for phpcs, phpstan, eslint, composer validations

Created a new MR with Gitlab CL. It's ready for review.

AstonVictor please resolve the conflicts.

@Viktor Holovachek looks test are failing on a GitLab CI pipeline. In DrupalCI test was green.

I'll check it

thanks

fixed tests.

thanks

Automatically closed - issue fixed for 2 weeks with no activity.