Fix for authentication in testing

[LokeSGJ]

Description

There was a major bug with authentication in testing where tests were not actually evaluating our auth policies, so we could not see if endpoints with authorization were working or not. With these changes, the testing environment should behave nearly the same as the production environment.

Since I was making big changes to every test, I also took the opportunity to streamline our test data seeders. The module is now much smaller and provides consistent and flexible data seeding with the methods in the DbSeeder class.

Three tests are still failing. They are all DELETE tests, and should be fixed by the changes on the Postgres branch. I've left them as they are to avoid needless merge conflicts.

Checklist

• My code is in the right place.\
• My code fully addresses the issue I was working on.\
• I have added appropriate tests and error handling.\
• My code follows the style guidelines.\
• I have added relevant comments explaining the purpose and function of my code (if necessary).\
• [] I have added relevant documentation to the GitHub wiki.\
• I have created a pull request and notified the teams.