The *postfix* role will now generate configuration and a lookup table
for [canonical address mapping][0] of email recipients. To configure
the mapping, the `postfix_recipient_canonical_map` must be a dictionary
of source-target addresses, e.g.:
```yaml
postfix_recipient_canonical_map:
my.bad.email@fake.test: my.real.email@example.com
```
[0]: https://www.postfix.org/ADDRESS_REWRITING_README.html#canonical
AWS is going to begin charging extra for routable IPv4 addresses soon.
There's really no point in having a relay in the cloud anymore anyway,
since a) all outbound messages are sent via the local relay and b) no
messages are sent to anyone except me.
The *postfix* role installs and configures the Postfix MTA. It currently
supports a number of modes, including direct transfer and relay. Relay
mode supports STARTTLS security and PLAIN authentication.