Add VQGAN-CLIP research project
# What does this PR do?
Implements VQGAN-CLIP using huggingface CLIP models

Related to #21064 

This Research Project allows users to generate or edit images with a single line of code. It wraps the huggingface CLIPProcessor class, allowing images to be processed as torch tensors in order to preserve gradient flow through the transformations. 

Features:
- Positive and negative prompts
- Multiple prompts
- Prompt Weights
- Creating GIF animations of the transformations
- Wandb logging

Tagging @amyeroberts for review :)

_The documentation is not available anymore as the PR was closed or merged._<|||||>Hi there,
Thanks for the feedback, I fixed the style issues and removed the face image. 
Also refactored the code to have more accurate function names, used just the tokenizer, changed the assertions to exceptions, and removed some extraneous code (eg double crop, freeze_module)
Have a great day :)
Erwann<|||||>@ErwannMillon - thanks for the updates. It's looking good 😎 ! 

Just two last things before I think we're ready to merge: 
* Removing the `face.jpg` file and instead pointing to a place where it can be downloaded
* Could you also remove the notebook? Like the image, we want to avoid adding large files as much as possible. Happy for you to link to e.g. a colab which shows this demo in the README. 