Add a shortfin pipeline for flux

[KyleHerndon]

No description provided.

[sogartar]

I was not able to review all the code. I will continue later.

[sogartar]

The main concern I have is there is a lot of code duplicated from the SDXL pipeline.
I am not sure when it would be best to address this, but we definitely need to address this at some point. When eyeballing this PR I think there is more than 1K lines of code duplicated.
I still have a bit left to review.

[KyleHerndon]

I agree that the code duplication is a major issue. There's massive duplication across flux/sdxl/llama pipelines and it makes me really uncomfortable to be duplicating this much but I was handed a mostly complete shortfin flux pipeline from Ean and I don't have as much expertise to make sensible abstractions and reutilizations. It might be a major effort to do a good refactoring across these shortfin pipelines, but if you think its the right move to do it now, I'll work on that.

[sogartar]

We already have a functional Flux pipeline in this PR. I will not block this to move things forward, but I think after that we need to refactor. It would be nice to involve the people who wrote the SDXL and Llama pipelines as they may have valuable design ideas.

[sogartar]

I did not see an integration test of the whole pipeline.
I think this is a next step and once it is under test we can focus on refactoring all the pipelines.