Set up for PHPUnit testing

[ChrGriffin]

This MR will do the following:

• Update the PHPUnit version to one that plays nicely with the current version of PHP and Laravel
• Minor config changes to set up to allow for sqlite database testing
• Update multiple migrations to account for sqlite (columns can't be non-nullable but have a default of null, and column drops need to be in their own database transaction)
• Add a User factory and a UserStatus factory (absolute bare minimum to be able to log in to the dashboard without errors)
• Change the HTTPS redirect middleware to only redirect in production (I needed this for local development, and it was a good excuse to add our first unit test!)
• Add a very basic feature test for the login page