Move more logic to DefaultContactBrowseListFragment

- PeopleActivity#configureFragments configures
  DefaultContactBrowseListFragment only, so it's moved to the
  fragment and is renamed as "configureFragment".
- configureFragment is now called from onResume instead of onStart,
  because we can count on onResume() being called after onNewIntent().
- onKeyDown() is also moved to fragment.

Bug: 30944495

Test: manual - navigate between fragments, rotate, press Back/Home/Recent
               button, search, multi-select and when no contacts view is
               shown.

Change-Id: I870760a816e53428e42362675545083b8e791d9a