As devops, I want to provide settings via the environment and disable the admin UI

[joeribekker]

The original library uses environment variables. In case environment variables for OIDC are set, this whole admin page should be disabled, a message showing "These settings are managed by your organization." and ofcourse the OIDC environment variables should be used INSTEAD of the database values.

The values passed in the environment should be shown on the page.

[sergei-maertens]

See maykinmedia/django-setup-configuration#1