* client/authority-discovery/worker: Extract address getter
* client/authority-discovery: Test for no duplicate p2p components
* client/authority-discovery: Append PeerId to Multiaddr at most once
When collecting the addresses to be published for the local node,
`addresses_to_publish` adds the local nodes `PeerId` to each
`Multiaddr`. Before doing so, ensure the `Multiaddr` does not already
contain one.
* client/authority-discovery: Remove explicit return