Migrate to Django 4.2 storage object syntax

[jkaeske]

Description

Django 4.2 changed the way storage objects can be defined. A subclassing in the storages.py is not necessary anymore and storages can be defined like so in the settings file instead:

STORAGES = {
    "default": {
        "BACKEND": "storages.backends.s3.S3Storage",
        "OPTIONS": {
          ...your_options_here
        },
    },
}

Django-storages "strongly encourages" the switch to this way of defining the storage objects, as written in the documentation.

Rationale

This would be in line with django-storages documentation, simplify the code base by deleting the storages.py file, and would give an easy possibility to add more storage objects.

Solution

If it needs to be changed, I can do it.

[browniebroke]

Duplicate of #4443