Use database seeding to make testing/QA more efficient

[etrepum]

Follow-up to conversations that were had in #35

We should have a way to get a new QA instance up and running correctly in one step. This should sync any relevant data from the sandbox salesforce so that creating classes and other objects will work. It should likely also create at least one user of each type and one row of each model so that all of the app can be walked through without a minimal amount of manual steps.

Looks like django has a way to do this with fixtures https://docs.djangoproject.com/en/2.2/howto/initial-data/ and there are also third party libraries available such as https://pypi.org/project/django-seed/

A migration is not the best way to go, as that runs in all environments (and only once), we want something that we can initiate only for testing purposes.

[etrepum]

This should be sufficiently resolved by #42