[WIP] Clean Up Test Mods

[halotroop2288]

Changes

• Drops support for Gradle 7 (Unimined is built against Gradle 8.8 now)
• Renames the JUnit tests to fit with the new test mods (and not use underscores)
• Organizes the new test mods into a new testing/minecraft subfolder
• Combines the Cleanroom test mod into the 1.12.2-Forge-Fabric test mod and cleans up that project a lot.
  • MCP
    • Forge
    • Cleanroom
    • Fabric
    • Quilt
  • Legacy Yarn
    • Fabric
    • Quilt
• Combines the 1.2.5 tests into one test mod
  • Calamus
    • Feather
    • Fabric
    • Quilt
  • MCP
    • ModLoader
      • How to use processResources in a ModLoader / old Minecraft Forge project
    • Minecraft Forge
• Overhauls the beta 1.7.3 test mod, fixing the mapping and loader pairing
  • ModLoader will not work correctly on other mapping sets without modification
  • Added Minecraft Forge 1.0.7 to the modloader source set, it is optional.

Known issues

• Cleanroom crashes whenever an entry is selected in the mod list. This is probably a Cleanroom bug.
• Quilt does not work on any version before 1.0.0 as far as I can tell