Feature Request: Skip download on start

[shawnrushefsky]

I would like an option to skip downloading models when the api server starts, for the use case of only running custom models. something like a launch flag --skip-download or respecting Fooocus's launch flag --disable-preset-download.

On the reverse side of that, I would also like a launch flag for only downloading models at launch, and then exiting rather than starting the server. This would facilitate building a docker image that has all of the models preloaded. Something like --download-only as a launch argument.

[mrhan1993]

I am working for merge 2.5. I will fix --disable-preset-download not work. but download-only, I have no idea for this now. may be later or never