Add opt-out/opt-back link

Change-Id: I998b7ad3ecb0b7e815f9ff0d5f871267b91c109d
Mingle: https://wikimedia.mingle.thoughtworks.com/projects/multimedia/cards/703
Mingle: https://wikimedia.mingle.thoughtworks.com/projects/multimedia/cards/704
Merge "Add opt-out/opt-back link"