Email: Allow users to control "opt out" behavior

[dospromptman]

Currently, when emails are sent using the send emails action, if the sending user has the "Send Non-Commercial Email" permission, then we allow all emails to be sent regardless of whether the recipient has opt-out preferences set. If the user does not have this permission, then we automatically filter out emails for which the recipient has opt-out preferences set and allow all other emails to be sent.

We should allow the user to control the behavior of sending emails in the case where a recipient has opt-out preferences set. This could be as simple as letting them control the "filter" vs "send" behavior for opt-out recipients (if they have the relevant permission set which would allow them to override this behavior), or it could be more complex where it also indicates a user's opt-out preferences in the recipients list and allows the user to make decisions there (dependent on functionality which allows the user to manipulate the recipient list).