[Feature] Add mailsink to aliases

Some email addresses are polluted enough to just ignore any incoming mail. There's no easy way to do this in the MailU UI right now, you'd have to set up Sieve DISCARD rules which is non-trivial.

How about adding the following line to the default Postfix aliases config file:

devnull: /dev/null

This defines a mailsink "[email protected]" for all mail domains which silently ignores and dumps all incoming mails to this address. It can then be used in the MailU UI to configure additional aliases such as "[email protected] forwarded to [email protected]".

What do you think, a generally useful feature (at very little cost) or rather not?