[ETF] Entity Texture Features

[V2.5.12] beta

• added emissive horse armour support
• added emissive & random horse marking texture support
• added shulker head emissive and random texture support
• fixed an issue with biome textures reverting to vanilla after a time with certain property file configurations
• fixed a previous beta change that broke random physics mod entity ragdoll textures
• optimized a lot of code and reworded things for better mod compatibility