feat(ui): FLUX in linear UI

[maryhipp]

Summary

Adds support in linear UI for using FLUX as a main model for text-to-image, image-to-image, inpainting, and outpainting.

Does NOT include: LoRA support, controlnet support, IP adapter support, or upscaling. This means the only available layers on the canvas included in this PR are inpainting and raster layers. Support for the rest will be in subsequent PRs as the back-end is built out.

Related Issues / Discussions

QA Instructions

Options for FLUX generation settings:

Merge Plan

Checklist

• The PR has a short but descriptive title, suitable for a changelog
• Tests added / updated (if applicable)
• Documentation added / updated (if applicable)

[hswlab]

The node user interface is not quite self-explanatory for basic users, it would be great if FLUX models could be used like all the other models via the basic ‘text to image’ user interface. Is this a big challenge to adapt Invoke AI to make this possible or can we expect such a functionality to be available in the future?

[maryhipp]

The node user interface is not quite self-explanatory for basic users, it would be great if FLUX models could be used like all the other models via the basic ‘text to image’ user interface. Is this a big challenge to adapt Invoke AI to make this possible or can we expect such a functionality to be available in the future?

That is what this PR is doing 👍

[hipsterusername]

When switching to Flux from SDXL, bounding box can get put into a state that is whack/breaks - It's also strange to have the bounding box change sizes when canvas mode is selected.

[psychedelicious]

Looks great!

I changed one thing - drop the default steps from 50 to 30. Ain't nobody got time for that.