[enhancement]: Better prompt adherence with Ella

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Contact Details

_No response_

### What should this feature add?

Integrating Ella with InvokeAI would allow us to write more detailed prompts, which are followed more closely by SD.

The only unknown I have is if Compel (which is using OpenCLIP) would work well with ELLA (which is using a t5 LLM instead of CLIP), and what approach might be taken here to improve prompt adherence while not giving up on the advanced prompting syntax.

### Alternatives

_No response_

### Additional Content

_No response_