Add IRCv3 standard-replies

[vanosg]

One-line summary:
Capture IRCv3 standard-replies messages and log to the +s console flag.

Not much in terms of capability in the moment, but is used by future pending capabilities such as account-registration

Test cases demonstrating functionality (if applicable):

.dump register foo bar moo
[00:41:05] #-HQ# dump register foo bar moo
[00:41:05] [!s] register foo bar moo
[00:41:06] [s->] register foo bar moo
[00:41:06] [@] :irc.foo.uk FAIL REGISTER INVALID_NAME foo :Your account name must be at least 4 characters long.
[00:41:06] REGISTER: INVALID_NAME: Received a FAIL message from irc.valware.uk: Your account name must be at least 4 characters long.