Add model selection

[without-ordinary]

The model selection is hard coded.

I'm probably going to experiment with finetunes and currently the only way to swap models would be to replace the one stored in LLavacheckpoints/llama-joycaption-beta-one-hf-llava

A model selector would also give flexibility with future releases.

[without-ordinary]

I've been working on this issue.

https://github.com/without-ordinary/joycaption_comfyui/tree/rework