[enhancement]: upload model via model manager

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Contact Details

_No response_

### What should this feature add?

It would be great to have the ability to upload a model from your local machine via the web interface.

This would be useful for sites such as Civit which often only allow Model/LoRA downloads when logged in and that don't work well with / don't have an API key available in InvokeAI's environment.

Currently:

1. I download a LoRA or Model locally
1a. Maybe try it out with something on my machine quickly
2. I have to rsync it to my server running InvokeAI to the container volume path on the host
3. SSH to the server
3a. If some files are LoRAs and some are base models, move them around accordingly
4. chmod/chown
5. Find the path in the mounted container volume
6. Copy it
7. Load InvokeAI
8. Go to the model manager
9. Add model
10. From path
11. Paste the path in relative to the containers fs
12. Click search (weirdly pressing enter doesn't work here?)
13. Find the model I just copied across (would be good if these could be sorted by date added)
14. Import it
15. Refresh models

etc... which is a right pain in the bum.

Ideally there'd be either or both:

A) An "upload model" button that pops up a browser file dialogue to select a safetensors file to upload.

and/or

B) The ability to drag a safetensors model onto the invokeAI web interface and have it upload.

### Alternatives

_No response_

### Additional Content

Just an idea / super super low priority / a nice to have