add cmd to change source of data (so flist points to e,g, data on S3 but was built on FS)

[muhamadazmy]

We need to add an config sub command that can work on a .fl this command should be able to:

• Show which stored are used
• Show tags, and any other .fl meta data
• Edit tags
• Edit store

This is useful because people can move the blobs to a different store and then modify the .fl where to fetch it.

Also right now it can be possible to use the dir store then later upload the files to an s3 store then modify the .fl