Very basic expansion to automated testing docs

[laceysanderson]

This PR expands the Automated Testing documentation to get us started adding real Tripal specific testing information.

Specifically,

• Adds a tripal-focused testing section with toc table
• Adds a page discussing field testing from an ideal, complete standpoint.
• Adds a very brief page talking about testing Chado field storage and pointing to our existing tests as examples.

These added docs are not ideal or really complete but they are better than nothing 🤪 I started them ages ago and then took some time today to update them so that they could at least be made available rather then rotting in a branch somewhere... all the information provided is correct and current.

[laceysanderson]

Thank you so much for the detailed review @dsenalik! ❤️ I've made the changes you suggested and handled the broken link by removing it and adding EVEN MORE resources! 😍

For testing purposes I copied the following from the rendered web page when confirming the above changes:

• Official Drupal: Testing Documentation
• Official Drupal: PHPUnit file structure, namespace, and required metadata
• Official Drupal: Running PHPUnit Tests
• Official Drupal: PHPUnit Browser test tutorial
• Official Drupal: PHPUnit JavaScript test writing tutorial
• Drupal 8, 9, 10 Functional and Unit Testing (Automation Testing)
• Writing Automated Tests in Drupal 8, Part 4: Kernel tests
• Writing Automated Tests in Drupal 8, Part 3: Unit tests
• Drupal 8: Writing Your First Unit Test With PHPUnit