[enhancement]: Add a way to convert models to diffusers in bulk

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Contact Details

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### What should this feature add?

Converting models to diffusers can get very time consuming and get in the way of workflow.
What I would like to see is an option to convert all uncached models all at once, so that switching between models becomes more responsive.
I know there is a parameter to control the size of the model conversion cache but that only addresses models converted one at a time.
If you do have the disk space available, an option to convert everything in bulk would save a lot of time in the long run.

A logical place for this feature would be in the Model Management panel, with an option to convert all models.
There is already an option to convert one model at a time.
This would be about building a queue to convert all models currently not in the local cache of diffusers.

### Alternatives

It doesn't have to be an update to the UI. A command line option or batch file menu option would be fine.

### Additional Content

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