[Feature Request] - Automation of the download cycle

[SpudmanWP]

I'd like to set up my Tribler instance to be as hands-off as possible.
It's currently in it's own Linux VM but will be in a Docker container when that gets released for 8.x

To that end, I'd like to propose some features to support automation:

1. Given that Tribler already supports subfolders in the Watch folder, let those folders represent a "Category".
2. Have "Category" appear in a UI column for the download.
3. Have the ability to change the Category after a download has started.
4. When a file completes, move the Watch folder torrent file to a "completed" folder that mimics the Watch folder, including Category subfolders.
5. When a file completes, move the completed download folder to another location according to a rules-based filter (based on Category, Name, etc). The file should still be able to be shared after moving.

[qstokkink]

If you want this level of complexity, it's probably a better to make your own script.

Tribler supports a REST API that allows you directly read and modify your downloads. You can play around with this by browsing to http://127.0.0.1:12345/docs (where 127.0.0.1 and 12345 are the IP and port Tribler is running on).

For example, moving a download with infohash abcdefabcdefabcdef00 can be done with an HTTP PATCH request to http://127.0.0.1:12345/api/downloads/abcdefabcdefabcdef00 and the request body:

{
    "state": "move_storage",
    "dest_dir": "/some/directory"
}