feat: Make default directory configurable

[Helge666]

Problem I have a 1TB ssd to boot the system, and an 8TB ssd for large files like models. I suppose similar setups are pretty common.

But on Windows, the app absolutely insists to reside on C: Even when moving it manually to D: after installation, it'll re-create it's folders on C: again upon next start. The option to open the model folder doesn't remember the desired folder either.

I deleted the app for the time being, because I allow only software that I absolutely cannot live without to remain on C:

Success Criteria Please make the default folder configurable on installation, or at least, make the models folder configurable.