Add MaskGCT

[HeCheng0625]

✨ Description

Add MaskGCT

🚧 Related Issues

[List the issue numbers related to this PR]

👨‍💻 Changes Proposed

• Add MaskGCT (inference, demo, ckpt)
• Add codec related to MaskGCT

🧑‍🤝‍🧑 Who Can Review?

@jiaqili3 @RMSnow @yuantuo666

🛠 TODO

• Add MaskGCT/Codec code
• Add gradio demo
• Update README
• Add ckpt

✅ Checklist

• Code has been reviewed
• Code complies with the project's code standards and best practices
• Code has passed all tests
• Code does not affect the normal use of existing features
• Code has been commented properly
• Documentation has been updated (if applicable)
• Demo/checkpoint has been attached (if applicable)

[jiaqili3]

Looks great, thanks!

[yuantuo666]

@HeCheng0625 Thanks for your great work. How about adding a section in README to introduce the dataset used to train MaskGCT?

== Updated ==
I've already added this in the README.md

[RMSnow]

LGTM!