[Feature] IP Adapter

[okotaku]

Motivation

IP-Adapter: Text Compatible Image Prompt Adapter for Text-to-Image Diffusion Models

Results (Optional)

stable_diffusion_xl_pokemon_blip_ip_adapter

Checklist

Before PR:

• Pre-commit or other linting tools are used to fix the potential lint issues.
• Bug fixes are fully covered by unit tests, the case that causes the bug should be added in the unit tests.
• The modification is covered by complete unit tests. If not, please add more unit test to ensure the correctness.
• The documentation has been modified accordingly, like docstring or example tutorials.