Initial email notifications

[PizieDust]

Update mollymawk to be able to send welcome emails and verification emails.

[hannesm]

Thanks for implementing this feature. Would you mind to explain what the semantics of emails should be?

• some verification email is sent with a unique token (uuid) to verify the email address used for account setup?
• is this the welcome mail, or is the welcome mail a different one?
• what is the story about the resending that you implement here? who should be able to trigger a resend (and when)? is this a spam/dos possibility (since anyone can create an account using any email address, and it looks like even without email verification there's the possibility to "resend verification mail"?) or are only admins allowed to trigger a "resend pending verification mails"?
• what is the failure semantics, so if the sending of an email fails, is it retried?
• what is the connection semantics? if there are 200 accounts created, are there immediately 200 connections to the mail server established to send out mails, or is there a "process" that ensures there's a single connection (or 2 or 5) to the mail server, and mails are sent sequentially?
• is a mails sent to admin when an account is created (so that the admin can activate that account)?