`make docs` is broken on django-ida cookiecutter

[timmc-edx]

If you use cookiecutter-django-ida and complete all of the setup steps, then run make requirements docs, the docs build fails. There are a number of things that need to be fixed before it succeeds.

Acceptance criteria:

• make docs is added to the tests for cookiecutter-django-ida. Currently this would need to be added as a new step in the ci.yml GitHub workflow under the run_ida_tests job, but it's possible that these tests will have been moved to the actual Python unit tests by the time this ticket has been picked up. The test should run make doc_requirements docs or similar.

Known issues that will need fixing:

• cookiecutter-django-ida/hooks/post_gen_project.py needs to include extra_context["requires_django"] = "yes" just like the django-app cookiecutter does, otherwise there will be a failure when autodoc imports urls.py
• The template will need to be expanded to allow layered cookiecutters to specify what the Django settings module is; django-app uses test_settings and that is hardcoded into python-template's docs/conf.py, but django-ida will need to use {{ repo_name }}.settings.test or similar.
• There's some kind of issue with a logo reference (have lost the details, but just mentioning this because it will come up)