Remove django-compressor storage

[nikolas]

It looks like this was initially set up via these docs: https://django-compressor.readthedocs.io/en/2.4.1/remote-storages/#using-staticfiles

This entire package may not even be necessary for our setup anymore. It's worth testing things with the vanilla
django-storages S3 storage class. It was initially set up to resolve a specific issue which may have been fixed
upstream by now - looks like there's still been some back and forth on this:

• https://github.com/jschneier/django-storages/blob/master/CHANGELOG.rst#s3-5
• S3Boto3Storage raises ValueError: I/O operation on closed file. jschneier/django-storages#382