restore_scylla_manager_backup: move to Scylla Manager repo

[mmatczuk]

Code is migrated to https://github.com/scylladb/scylla-manager/tree/master/ansible/restore that is now publicly available.

[tarzanek]

docs point here, so we should setup a redir, too
( https://manager.docs.scylladb.com/stable/restore/index.html )

[tarzanek]

@mmatczuk thnx for fixing docs
I'd love to merge this
but then I have no clue why there is a conflict now, I'll check it and remove myself and close this
or if you will have time, you can try rebase and I will merge, tia

[mmatczuk]

Actually it has been moved to https://github.com/scylladb/scylla-manager/tree/master/ansible/restore