net-mgmt/rtrlib: Add the port to the tree and pass maintainership to the submitter
The RTRlib implements the client-side of the RPKI-RTR (RFC 6810) and
BGP Prefix Origin Validation (RFC 6811).

PR: 225645
Submitted by: Felix Annen <freebsd@bodems.net>
Reported by: Felix Annen <freebsd@bodems.net>
Reviewed by: olivier