WhisperPush: add Privacy Policy links

* One in preferences overflow menu (and ToS)
* One on the bottom of the registration activity

Change-Id: I61b8674381fb525d35f762f01e7ee6cdb4e9d03e
Signed-off-by: Roman Birg <roman@cyngn.com>
Merge remote-tracking branch 'github/cm-11.0' into HEAD