Extract sprite_material functions, bindings, and types to separate shader modules

[cookie1170]

Objective

Make it easier to make sprite shaders by extracting the functions, bindings, and types from the SpriteMesh's sprite_material.wgsl shader to exported modules

Solution

Move the SpriteMaterial type and flags from sprite_material.wgsl to the bevy_sprite::sprite_types module

Move the sprite material bindings to the bevy_sprite::sprite_bindings module

Move the uv flipping, tiling, transforming, and slicing logic along with some utility functions to the bevy_sprite::sprite_functions module

Testing

Ran the sprite_* examples using SpriteMesh and manually verified that the shaders compiled and the behaviour matched