Improve Documentation for Model Architecture and Usage

[luna2terra]

Description

The project lacks comprehensive documentation explaining the RelaCtrl architecture, its components, and how different parts interact. The README provides basic installation and inference steps but doesn't adequately explain the model's architecture, the significance of different parameters, or how to train/fine-tune the model.

Specific Issues

1. Missing architecture diagram or detailed explanation of RelaCtrl's approach
2. No documentation on the significance of parameters in the TDSM and RGLC_Block classes
3. No explanation of how to train or fine-tune the model
4. Insufficient documentation for the RelactrlPixArtMSHalf_RelaCtrl class and its relationship to PixArt

Proposed Solution

1. Add an architecture section to the README with a diagram illustrating RelaCtrl components
2. Add docstrings to key classes and methods explaining their purpose and parameters
3. Provide a training/fine-tuning guide with examples of how to adapt the model
4. Document model hyperparameters and their impact on generation quality
5. Include more examples of different use cases beyond the basic ones provided