(docs): add a README in test_project for more explicitness

- in case someone stumbles into the tests and aren't sure what they're
  looking at -- a README appears!
- also to be more explicit about some decisions around why some Django
  specific files exist and why others don't (as minimal as possible)
- and finally to give directions on how to run the tests, as it's not
  from inside the tests/ directory

Author: agilgur5

tests/test_project/README.md

@@ -0,0 +1,6 @@
+# Django Test Project
+
+This is a barebones, as-minimal-as-possible Django project that is solely meant for testing.
+Outside of the actual test files, the other files are the minimum configuration necessary for getting this project to run with `pytest-django`.
+
+In order to run these tests, see [maidfile.md](../../maidfile.md) in the root directory of the repo.