Resolve #3468719 "Gitlabci fix eslint"
https://www.drupal.org/project/colorbox/issues/3468719
Fixed ESLint errors on GitlabCI:
- Fixed all validation errors such as unnamed functions, variable names, indentations, etc...
- Tried moving away from JQuery to Vanilla JS, where possible.
- Ignored certain lines of code which would need to be refactored to vanilla JS (
jquery/no-
rules). - GitlabCI build: Required ESLint tests to pass.