[Feature] Support Batch Textures

[ACMLCZH]

• Support batch textures in gs-madrona. Using gs.morphs.BatchTextures in Genesis side to add batch textures for diffuse_texture. It will render different image textures for different envs. Used for domain randomization.
• If a BatchTexture has n images, it the i-th env, it will show the i % n-th image.
• See examples/rigid/single_franka_batch_render.py for example usage.

[YilingQiao]

We need to do minimal change in one PR next time. Seperate the coding style change from the feature change.