Simplify testing suite with Vitest

[yeoffrey]

TL;DR

The current testing suite is overly complicated. Since we've moved over to Vitest (see: #1242), we should now that package to its full potential, and simplify the testing suite all together for this project.

More Detail

Currently the testing suite basically has a "runner" which is in index.test.ts which handles all the tests in the testing suite. It imports configurations from /validation which will then be imported with the runner and it will execute tests.

The problem here is that is super complex. It also feels like a blackbox a bit because its not super readable and its not very strict. Now that we are using Vitest, I think theres a great opportunity to make this easier to understand and also more reliable.

Goals

• Report code coverage
• Remove Babel now that we are using Vitest
• Allow users to use the watch feature while testing
• Simplify types in testing suite.
• Make the testing suite easy to read and add to.