* Add port parsing support to parse_wireaddr. This is in preparation for storing
addresses in the peers table. This also makes parse_wireaddr a proper inverse of
fmt_wireaddr.
* Move parse_wireaddr to common/wireaddr.c this seems like a better place for
it. I bring along parse_ip_port with it for convenience. This also fixes some
issues with the upcoming ip/port parsing tests.
Signed-off-by: William Casarin <jb55@jb55.com>