netloc is the public access point to a caucase instance.
bind is the private access point to a caucase instance, which may be
different (ex: NAT). Allow overriding netloc address with --bind.
As a consequence, add support for multiple binds: a netloc may resolve to
multiple addresses (ex: one IPv4, one global IPv6 and one Unique Local
Address).
As a further consequence, systematically disable automatic IPv4 binding
when binding to an IPv6 address.
Also, allow overriding netloc port with --base-port. The same port pair
will be used on all bound hosts.
Share SSL context between multiple https sockets.
To increase binding visibility, print bindings, and print when exiting.