[Add] VEnhancer - the interpolation and upscaler for CogVideoX-5b

### Model/Pipeline/Scheduler description

VEnhancer, a generative space-time enhancement framework that can improve the existing T2V results.

https://github.com/Vchitect/VEnhancer

### Open source status

- [X] The model implementation is available.
- [X] The model weights are available (Only relevant if addition is not a scheduler).

### Provide useful links for the implementation

_No response_