[enhancement]: Transparent background generation with layer diffuse.

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Contact Details

roughweiler@outlook.com

### What should this feature add?

I just stumpled over the layer diffusion models and the linked expanseion for SD webui (automatic1111)... would it be possible to add this functionality in invokeai as well? That woul dbe a great benefit for using invokeai in more traditional image editing workflows.

https://github.com/layerdiffusion/sd-forge-layerdiffuse

### Alternatives

_No response_

### Additional Content

_No response_