This adds support for listening on a Unix socket for administrative
connections, that then use a simple protocol for communicating with
the service (BouncerServ) as an administrator with a global context.
The wire format used by the Unix socket is IRC, but without
registration or overheads.
Example session:
>>> BOUNCERSERV
<<< 461 * BOUNCERSERV :Not enough parameters
>>> BOUNCERSERV :n s
<<< :gensou FAIL BOUNCERSERV :this command must be run as a user
>>> BOUNCERSERV :u s
<<< :gensou PRIVMSG * :marisa: 2 networks
<<< :gensou PRIVMSG * :alice: 1 networks
<<< :gensou BOUNCERSERV OK
Add a new flag to disable users. This can be useful to temporarily
deactivate an account without erasing data.
The user goroutine is kept alive for simplicity's sake. Most of the
infrastructure assumes that each user always has a running goroutine.
A disabled user's goroutine is responsible for sending back an error
to downstream connections, and listening for potential events to
re-enable the account.
This is a mecanical change, which just lifts up the context.TODO()
calls from inside the DB implementations to the callers.
Future work involves properly wiring up the contexts when it makes
sense.
