LFS prune on remote

Some customers are using LFS in the repository and they want to save space issues when frequently updating an existing LFS object/file.

Currently, what they're doing is to LFS prune their local copy of their repository.

However, for LFS remote, they will need to manually delete the updated object/file each time it was updated.

It's best if we can have an option for users to be able to prune their LFS remote so that there's no need for them to find then remove each file (in LFS) that was updated.