Need to implement texture loading support for all formats in tryLoadTextureBuilders().

Going to keep it alongside TextureBuilderIdGroup and eventually delete the others.

Probably going to always pass a palette with texture builders no matter what, since the renderer interfaces need to work with both paletted and true color.

Each frame of an entity animation, etc. should be able to use this for indirect texture references with the texture manager.

This should be useful when trying to allocate entity animation keyframes without worrying about texel data.

The Renderer drawing API is currently broken with several not-implemented macro placeholders and will need to be changed to internally allocate Texture instances for TextureBuilderID + PaletteID pairs as an interim solution to the renderer returning allocated texture handles. Much less of the codebase makes assumptions about textures being 8-bit now, which is a big improvement.

ArenaPaletteName and ArenaTextureName provide direct string references to original assets, instead of having to go through an unnecessary enum-to-string step.

The renderer will handle converting texture builders to SDL textures temporarily until a better design is used where the renderer returns allocated texture handles for users of the renderer to keep track of.

Cleaning up the Texture class a bit.