Feature/setup basic e2e testing framework

[max-uni-hd]

This is unfortunately a rather big PR. Some information up front:

The purpose of this PR was to add a basic E2E testing setup and basic E2E tests to make it easier to spot errors when changes are made to the code base.
I also added some sample unit and integration tests.

I have tried to add everything you need to review in the README.md, starting at line 88.
But as a summary:

Important
For the E2E tests to work, you have to put the file db_out_full.json in the folder specified in the env variable DJANGO_TEST_DATA_DIR.
As this file might at some point contain proprietary data, it is not committed
for now. This might change in the future. To get this file, reach out to me (or if you have access to the server, it is under /opm-data/test_data).

If you want to run the e2e tests, use the following command:

docker compose -f compose.base.yaml -f compose.prod.yaml -f compose.e2e.yaml up -d
# this will start up all the containers and run the e2e container, which runs the tests as well
# so, run the next command also to see what this container is doing
docker compose -f compose.base.yaml -f compose.prod.yaml -f compose.e2e.yaml logs -f e2e

Once the container is done, you should (hopefully) see something like this:

e2e-1 | ============ 41 passed, 2 skipped, 48 warnings in 102.09s (0:01:42) ============

(Don't mind the warnings: in my case they are "just" deprecation notices.)

You can run them again locally (given you installed all the dependencies) via pytest custom_code/tests/e2e -rs or via

docker compose -f compose.base.yaml -f compose.prod.yaml -f compose.e2e.yaml up \
--abort-on-container-exit --exit-code-from e2e

to start the container again.

Not "too production relevant" changes
The impact on the regular app should be small or non existent, because the only changes that were made here were:

• add data-testid attributes for easier selection in templates
• some whitespace changes
• fix minimal html "errors" that were causing problems in tests
• add 2 endpoints for testing

These should be all the files with such changes:

• custom_code/templates/custom_code/prob_list.html
• templates/tom_common/index.html
• templates/tom_registration/partials/pending_users.html
• templates/tom_targets/partials/aladin_finderchart.html
• templates/tom_targets/partials/target_data.html
• templates/tom_targets/target_detail.html
• templates/tom_targets/target_grouping.html
• templates/tom_targets/target_list.html
• templates/tom_targets/target_list.html
• custom_code/views.py
• galactic_science_opm/urls.py

Most of the other changes are under custom_code/tests and should have no impact.

Changes with impact on app
I have refactored the way we use docker compose quite a bit and that will have an impact on the startup scripts on the server.

I also made some changes to the Dockerfile, but nothing major, I think. It ran on my machine™. I hope it also runs on the server. Once the staging environment is done, I will test it thoroughly.

[mpgh]

In the long run, the lightcurves should always be available. If it needs to be, empty. The radar plot, however, is tied to the microlensing science case and we expect it will look different for the second use case.

[mpgh]

I have checked the nominal structure. Details w.r.t. prod are left for @astroadmin to comment on. As far as the plots are concerned, some are required to appear, some are optional. This is not reflected in the code base, yet. For the time being, this looks reasonable.