cli: add reverse alias to DID lookup
Add a subcommand for looking up a DID by providing an alias. This can obviously return more than one DID since aliases are not unique.
Would be also nice to have this for filtering, for example 'rad patch list --authored someone' instead of '--authored '. I know that it might be complicated to get this right especially since that alias might return multiple DIDs, but UX-wise I think it would be a good idea