FEATURE REQUEST: Implement resubscription to email subscriptions

[sambuca1g]

Problem: There's currently no way to resubsribe to an email newsletter. Once unsubscribed, no more emails are delivered to the whole account not just an alias. If the user wants to resubscribe it's no longer possible to do so. This is very impractical.

Solution: Perhaps a Resubsribe button? Or an option to remove the subscription from the blacklist?