Modular ImageBind - Load modules based on selected modailites

[ahmedsaed]

[!NOTE] This PR depends on #136 and includes it's changes. Please review #136 first.

This pull request introduces a modular implementation of ImageBind, enabling selective loading of modality-specific components for more flexible and efficient multimodal inference.

• New Script: Added imagebind/model_splitter.py, which splits the ImageBind model by modality and saves individual modality-specific weights for streamlined deployment.
• Modular Architecture: Introduced the ModularImageBind class in imagebind/models/modular_imagebind_model.py, allowing dynamic loading of only the required modalities during inference.