[Pipelines] Add BLIP diffusion

[sayakpaul]

BLIP diffusion (Salesforce): https://dxli94.github.io/BLIP-Diffusion-website/

BLIP diffusion enables subject-driven zero-shot image generation which is probably its best USP.

• Code with pre-trained weights: https://github.com/salesforce/LAVIS/tree/main/projects/blip-diffusion
• Paper: https://arxiv.org/abs/2305.14720

From the official website mentioned above:

[ayushtues]

Hey @sayakpaul I'll be interested in contributing to this model, will try to start a PR soon

[ariG23498]

Just noticed that this is done! I think we should probably close this issue ^_^