Enhancement Expansion of support for WorldGenerators

[Dev7ex]

The WorldGenerators should support the following things in the future.

• WorldGenerator files. This means that the user should be able to create a script in which he can decide for himself how what is generated.

• WorldGenerator with single biome support

• Ability to assign arguments to WorldGenerators already known from the CleanroomGenerator plugin

[ElTuna]

yes please, I'm using the command world import spawn CUSTOM -g CleanroomGenerator:. and it says The specified generator -g does not exist 😭