Provide Option to run the heavily liften in a lower priority thread in windows

### Feature Idea

When a big model spins up, ComfyUI uses all my 32GB of Ram. It's okay that it uses it, it's there to be used. However, it often spins it up in a way where the system freezes a bit.
Currently, I need to manually reset the priority in the Task Manager to lower to prevent this. I think it would be great if there would be a general setting to specify the priority with which the ComfyUI background process is supposed to run.