Send confirmation email after registering #636

Is your feature request related to a problem? Please describe.

You can't be sure that the email you used to register was correct
Spammers can create a lot of accounts very easily
Someone else can use your email (even if I don't know why anyone would do that?)

Describe the solution you'd like

Send a confirmation email when creating an account.

Accounts created from the CLI should probably be immediately confirmed.

~~Describe alternatives you've considered~~

Additional context

From #635

Someone else can use your email (even if I don't know why anyone would do that?)

someone could sign up in your name, and leave hateful comments.

I'm not even sure admins can see a user's email address at this point, so doing this would not really impersonate the email owner. And doing it using their pseudo is probably unavoidable, and far more effective to discredit someone

Would love to see some form of notification to admins whenever a new account is created.

A very primitive way to do it is to BCC confirmation emails to admin's email address

Also, want to see support of ESPs such as SendGrid, Mailgun. Thanks!

You should open a new issue for supporting ESPs, the two you named seems to have some rust bindings so it should not be too difficult, but if it stay here as a comment, it will definitely get forgotten