Removed unused Codeception test code

[marcusmoore]

Description

This PR removes the old Codeception test code. These tests haven't been run in a long time and we've decided to move forward with Dusk for future browser testing.

Type of change

• Clean up

[what-the-diff]

PR Summary

• Large-scale deletion of test and configuration files
  The main theme of the changes in this pull request involves the deletion of a substantial number of test and configuration files. This includes file types such as '.php', '.yml', '.txt', and '.gitignore'. The impact of these deletions may vary depending on the relevance and usage of these tests and configurations in the work-flow. It's worth noting that no new files have been added.

• Removal of 'assets', 'api' and 'functional' related test files
  A significant number of 'assets', 'api', and 'functional' related test files have been removed. This suggests a change or potentially a simplification in how the system functionality and API's are being tested.

• Erasure of Codeception related files
  Multiple Codeception related configuration files and test scenarios have been removed. Codeception is a testing framework, the removal of these files might indicate an alteration or overhaul of the testing strategy or a switch to a different testing tool or framework.

• Deletion of 'ApiAccessories', 'ApiAssets', 'ApiCategories', and 'ApiCheckoutAssets'
  Complete removal of 'ApiAccessoriesCest.php', 'ApiAssetsCest.php', 'ApiCategoriesCest.php', and 'ApiCheckoutAssetsCest.php' points towards changes being made to how certain elements such as accessories, assets, and categories are being handled or tested in the API.

• Removal of other testing and helper files
  Removal of files such as 'Helper/HTMLValidator.php', 'Helper/Unit.php' and 'UnitTester.php', among others, denote a significant restructure of the testing methods and tools used within the project.