1.21.1 more foxes

[Akinesis]

Rework on how fox variants are registerd, making it a little more data-driven.

Added more foxes variant :

• Variant for Taiga, Snowy and Default foxes.
• Varaints for spawnable foxes in the Nether.
• Desert fox (Fennec)
• Spawnable foxes in the End with a nex varaint and rare chance of Talon's one.
• Monster variants that can spawn at night.
• Sculk variant spawnable in the Deep Dark

For now, all variants are identics in functionality. There's room for adding custom behaviore/attributes/components when spawning.
Fox spawn weight on biomes where they would not spawn in vanilla are hard-coded magic numbers for now. Might be a good idea to put that (and a togolable option for each variants) in a config file ...
Artists / Ressourcepacks used for the new models are in the readme of this branch.

[TalonFloof]

Love these changes ^w^

I'll do some playing around with it later, and if everything goes well I'll merge this to main.