GitlabCI: Fix Stylelint validation errors

Quick follow-up on this issue:

Fixed all stylelint validation errors based on report and required job to pass.

Mostly automated fixes, except for the stylelint rule selector-id-pattern which had to be disabled in all reported CSS files:
These CSS IDs can't really be changed since they are provided by the Colorbox JS library.

In other words, changing these CSS IDs would break module's styles.

Last pipeline with stylelint job completed successfully 🟢

• MR pipeline: https://git.drupalcode.org/issue/colorbox-3466984/-/pipelines/248258
• Stylelint job: https://git.drupalcode.org/issue/colorbox-3466984/-/jobs/2385042

 
We would greatly appreciate if a maintainer or someone with write permission could take a look at ticket's merge request MR!38 and let us know if there would be any more work needed.

Feel free to let us know if you have any questions or concerns on any of the changes in the merge request or any aspect of this ticket in general, we would surely be glad to help.
Thanks in advance for your feedback and reviews.

@DYDave, thanks for the patch! Merged MR 38.

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