This moves the import of `jquery.waitforimages` from main to
- `app/assets/javascripts/commit/image_file.js`
- `app/assets/javascripts/pages/projects/show/index.js`
- `app/assets/javascripts/pages/projects/tree/show/index.js`

These are the only files which utilize it and thus we don't need to load
it on every page.

The issue to replace it completely can be found here:
https://gitlab.com/gitlab-org/gitlab/-/issues/219370