Feat/test setup

[TeddyRoncin]

Description

This PR is the first part of the split of PR #37 It introduces the base test class (EtuUTTApiTestCase)

Checklist

Test

Implementation

• [ ] Files and variables have a name explaining what they do.
• [ ] Updating the DB schemas and seeding the tables do not generates errors.
• [ ] All code repeted more than 2 times has been refactored in a dedicated file or function.
• [ ] Debugs have been removed : dd() | dump()

Tools

• [ ] PHP CS Fixer has fixed all files inside the src folder.
• [ ] All commits have been done using Commitizen.

Documentation

• [ ] All new classes and non-trivial functions have a code documentation.
• [ ] There are comments to explain complex parts inside your code.
• [ ] If a new folder is created, it has been added and explained inside the "Folder structure" part of the README.md file.