Feature Request: Allow manual sending of email confirmations

[techknowlogick]

This is a feature request to allow toggling of automatic email confirmation emails.

The reason behind this request is that while ratelimiting on signups would be helpful, gitea.com (and other public gitea instances) can receive many signup requests (even for invalid emails) across many IPs. There are very clear patterns for the spam attacks, and so perhaps for larger instances it'd be helpful if instead of auto-sending emails we have an admin mail things out (via button in admin dashboard,etc..). This would also allow admins to re-send verification emails if something states they didn't receive the original email.

[wULLSnpAXbWZGYDYyhWTKKspEQoaYxXyhoisqHf]

this is a great idea, I second this.
enough (as few as one!) people register with bogus addresses of some Big Name, Gitea sends out "registration confirmation" emails, for which they never asked for, they report the emails as spam and then you have to pretty please the likes of Spamhaus (personal experience... [1]) for de-listing of your {domain,IP}s.
I have since made use of both the email allowlist Gitea offers and disabled "registration confirmation" emails just to make sure (for now), but this would be much more granular.

refs:
[1] https://git.dotya.ml/dotya.ml/hostmaster/issues/1