Shows trash category in Storage Settings

If there is APP which supports VIEW_TRASH intent,
use it to show trash files. Otherwise popup a dialog
to guide users to empty trash files.

Bug: 189109564
Test: manual visual
      Observe size information are the same as files in Files APP.
      Observe if empty trash button empty trash files.
      Observe if Trash category update summary and order after emptying
      trash files.
Change-Id: Ia3c46dcb1b4fadcdfb865f7dd315c27f8f98cb2c