pgp: Simplify gpg-agent setup

We can use a config file to set default options for the daemon. That's
nice. That means we don't have to hack around launchd by using an
external launch script.

We're also bumping the default cache from 10 mins to 1 hour, which seems
more reasonable.
mutt: Save FastMail sent emails

Turns out I wasn't saving any outgoing emails from FastMail. Setting
`record` (and unsetting it for gmail) fixes that.