Permit rendering scenes imported into specified file

[rvodden]

Overview: What does this pull request change?

Motivation and Explanation: Why and how do your changes improve the library?

Links to added or changed documentation pages

Fixes #4462

Further Information and Comments

Reviewer Checklist

• The PR title is descriptive enough for the changelog, and the PR is labeled correctly
• If applicable: newly added non-private functions and classes have a docstring including a short summary and a PARAMETERS section
• If applicable: newly added functions and classes are tested

[henrikmidtiby]

Thanks for the PR.

I consider if the workaround provided here #4462 (comment) would be enough, or whether we have to add this functionality to the code base.
If it should be added to the code base, some tests of get_scene_classes_from_module and scene_classes_from_file should be added to this PR.

[rvodden]

Thanks @henrikmidtiby - I can easily add those tests.