Add Gutenberg AI Tools to Gitlab CI for automated testing

I added the .gitlab-ci.yml with some modifications and it works as expected, I'll leave it for "Needs Review" for a while, then I'll mark it as "Fixed": https://git.drupalcode.org/project/gutenberg_ai_tools/-/pipelines/412012

I'll create a separate issue to fix the ESLINT/ CSPELL / PHPCS and PHPSTAN issues.

I'll merge it to the 1.0.x branch as well

I move this to "Fixed" since it seems to be working (the Gitlab CI Reports)

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