[core 3.70 compat] Django storages config deprecation

[pedro-psb]

Action for django's storages deprecation:

1. Pre or on core-3.70 compat declaration:
   • Replace legacy with new (not required)
   • Settings on signal-handler (not required)
2. On core 3.70 compat declaration: (closes this)
   • Use new setting in one CI scenario

See for context:
https://discourse.pulpproject.org/t/action-required-plugins-should-use-djangos-new-storage-config-for-3-70/1866

[hstct]

We don't have any occurrences of using DEFAULT_FILE_STORAGE in pulp deb. Is it sufficient to just do this step then? -> Edit the .ci/ansible/settings.py.j2 file

Or do we need to move settings to class level as well?

[pedro-psb]

Yes, only 2 is required here.
This week we noticed the file settings.py.j2 is managed by pluging_template, so there is a minor update on this step.
You should:

1. Add test_storages_compat_layer: true to template_config.yaml
2. run plugin-template

Example in pulpcore