Extension of the file rename feature

[09eragera09]

Is your feature request related to a problem? Please describe

Problem: I have a self hosted booru. Said self hosted booru is a mirror of xbooru, however xbooru has contributors that edit tags even long after the image has been uploaded. I wish to grab the most updated tags once every 6-12 months.

Describe the solution you'd like

It'd be nice if the "rename existing images" feature could be extend to instead do the following:

1. "save" images instead of renaming them (thereby using all the logic of a normal picture being saved, including the 'moving', and the post-saving scripts being run). This way I can just write my own script to then update the booru instead of making new entries.
2. add a timer per request (variable, anywhere from 0.1s to 5s), such that the service is not ddos'd and rate limits are avoided.
3. (Optionally) automatically grab every image from a network location or a booru service, instead of a local dir.

Describe alternatives you've considered

Using grabber CLI to download the json data of all the images on Gelbooru, and then writing a script to compare against the database and manually changing each entry.

Additional context

This would really extend Grabber's booru creation and maintenance features, imo it's be great.