Resolves#1494
Allow signed-in users to rate, review, edit, and delete an installed app's
review directly from its details screen. The form is hidden from anonymous
accounts and only shown for installed apps.
Submitted reviews are cached locally in a new Room "review" table (db v9) so
they appear immediately while Google publishes them, and are reconciled with
the Play API: edits made on the Play Store are mirrored, and a review deleted
there (or via the new delete action) is removed locally. Deletion relies on
gplayapi 3.6.3.
753c7fa06a