Sends email with information on the new user (time of creation and time of last sign-in) and a link to manage the new user from the admin panel
closes: https://codeberg.org/forgejo/forgejo/issues/480
Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/1371
Co-authored-by: Aravinth Manivannan <realaravinth@batsense.net>
Co-committed-by: Aravinth Manivannan <realaravinth@batsense.net>
