Remove the composer libraries workaround

Apologies for the crazy number of commits attempting just to get a working test. I had a hell of a time because I didn't think to ensure the test user was logged in to view the node/add page to test the field widget. oi vey.

But, the really cool thing is, I got a GitLab CI customization and browser tests (inspired by DropzoneJS) implemented!

This CI composer job and testing nicely covers the exact instructions now provided in the readme and ensures the widget gets the intl-tel-input flag select in place.

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