Allow emails with "+" in email catchall address
I triend to create a catchall email for a domain and send it to firstname.lastname@example.org. I got the error
Destination is no valid email address.. I searched the code and found that in https://git.ispconfig.org/ispconfig/ispconfig3/blob/master/interface/lib/classes/tform_base.inc.php#L1044 there is a validation check to not allow "+" signs in the email. I suppose it is for the moment when you create a mailbox on the server.
Allow "+" sign in emails that are as recipients, in Email Catchall, Email forwarding and others.
Add a parrameter that will allow skipping of the check. We have a
separator parameter so I think it's possible to add another one.