Backend Confirmations and Opt-Out

[Astor]

Implement confirmation emails for each aspect:

• Contact : Should return an email, confirming subscription,assuring contact will be made by a team member and a thank you.
• Volunteer : Should return an email, confirming subscription,assuring contact will be made by a team member and a thank you.
• Newsletter : Should return an email, confirming subscription.

Implement the Opt-Out to allows users who are part of the Campaign to Opt-Out of receiving emails.