Add hamburger menu to PeopleActivity

1. This CL moves "settings" and "help & feedback" to hamburger menu.
2. Changes in people_activity.xml may be hard to read. We just wrap the
   existing content of people_activity.xml with DrawerLayout and add a
   NavigationView below it: https://paste.googleplex.com/6376771465248768
3. Screenshot https://goto.google.com/contacts-hamburger

Bug 27687799

Change-Id: Ia8ce3746cee9ad63689157dbe0b1ea81200bedf6