* implement authentication via token for relaysrv
Make replaysrv check for a token before allowing clients to
join. The token can be set via the replay-uri.
* fix formatting
* key composite literal
* do not error out if auth material is provided but not needed
* remove unused method receiver
* clean up unused parameter in functions
* cleaner token handling, disable joining the pool if token is set.
* Keep backwards compatibility with older clients.
In prior versions of the protocol JoinRelayRequest did not have a
token field. Trying to unmarshal such a request will result in
an error. Return an empty JoinRelayRequest, that is a request
without token, instead.
Co-authored-by: entity0xfe <entity0xfe@my.domain>
