[enhancement]: Add space validation function on payload retrieval and execution.

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Contact Details

Discord: Fl1nt

### What should this feature add?

I'd like to get a helper/util function that would check for remaining space available before downloading models/loras/etc.
What would also be very helpful would be to have an execution planner function that would look for the amount of memory that a run will take (roughly) and compare it to the available VRAM.

Using both function, the program could raise a user/error message before any action is taken and avoid crash at mid-execution/download.
Using both function would also allow the program to show a progress/usage bar of the vram/disk space while setting for a generation.

### Alternatives

None, discard this request ^^
This is a day 2 operations improvement request that do not block anything but would improve user experience.

### Additional Content

_No response_