Forward important emails to the Staff category

We have the private Staff category already, so it would make sense to forward all the important emails from to this category as new posts.

@Epictek notes that Discourse supports this natively:

We should implement this, but it looks like we may need to setup reply-by-email first. This is relatively simple to do:

Freeside uses the GSuite thingy for email, so it’s a case of logging in as and setting up a dedicated account for it to use.