Add TOOTCTL command for adding domains to E-mail Blacklist

Fediverse is currently being filled with hundreds of BOT accounts by a (or a few) actors with questionable intentions. See the following threads:

Our current list of bot creating email domains includes roughly 200 domains (growing every day).

The E-Mail blacklist feature seems to be very effective against such “attacks” because of the way it is was implemented (resolving MC records and adding those as well).

Now it would be great, if one could take our ever growing list of bogus email domains and shoot them into the E-mail Blacklist with a TOOTCTL command.