[Mass Email Sender] Add Bcc Email-Adresse for Mass E-Mail Sender for GDPR

GDPR requires us to be able to prove that our users have read and accepted the new privacy policy and terms and conditions. If we want to send information to the user via the current Mass Email Sender Plugin, we do not have this confirmation. However, we would have the confirmation that every email that is sent will also be sent to a Bcc address.

So my suggestion:

Add Bcc Address to Mass Email Sender Plugin :slight_smile: