WebSocket connections allow web-based clients to connect to IRC. This
commit implements the WebSocket sub-protocol as specified by the pending
IRCv3 proposal [1].
WebSocket listeners can now be set up via a "wss" protocol in the
`listen` directive. The new `http-origin` directive allows the CORS
allowed origins to be configured.
[1]: https://github.com/ircv3/ircv3-specifications/pull/342
Users can now specify multiple "listen" directives in their
configuration file. If -listen is specified on the CLI, it's added to
the list of listeners.
Listeners are now parsed as URLs. If the scheme is missing "ircs" is
assumed. URLs allow to enable/disable TLS on a per-listener basis and
will be used for Unix sockets too.
The default listening address is changed from irc+insecure://:6667 to
ircs://:6697. This avoids setting up an insecure listener opened to
everybody.
Add bouncer logs, in a network/channel/date.log format, in a similar
manner to ZNC log module. PRIVMSG, JOIN, PART, QUIT, MODE are logged.
Add a config directive for the logs file, including a way to disable
them entirely.
