Create User Preference Setting for Alarm+Ringer Mode Association

Context: go/wear-conditional-mute-alarms-with-ringer-mode
We want to separate the user's preference for the association, from
the real state of whether or not the association should occur. This
will help to use factors other than the user's choice when deciding
if the association should happen.

Bug: 317405434
Test: presubmit
Change-Id: I83e82ade7b9d1da2aa4a9cf923c5e162b135e0f5