Move converted files to 'converted' subfolder

[truth1ness]

I would love it if HandbrakeBatch could move converted files to a subfolder after conversion so you have a backup copy in case you want to change anything.

This is my biggest headache when mass converted many files in nested folders. It's not a problem if they are non-mp4 files, but when I'm converting mp4 files they will get overwritten. In Handbrake it's even worse because I have to go into every nested folder, create a 'converted' subfolder, move the files into it, add them to Handbrake, set the destination to the original folder, and repeat this for every single subfolder.

There is another ticket to move converted files to Trash which is good, too, but I think this is the ideal solution because if you are doing a large batch with many folders it can be difficult to recover them from Trash where they get all mixed up with other batches.