Add "Instant apps" filter to app listing

Bug: 35098444
Test: automated testing of ManageApplications is hard (b/34768986), so
testing is manual for now: install at least one instant app and then go to
Settings->Apps&Notifications->Apps and see if the filter lets you see
only instant apps.

In Settings->Apps&Notifications->Apps, the list of filters before this CL is:

 All | Enabled | Disabled

With this CL, the filter list becomes:

 All apps | Installed apps | Disabled apps | Instant apps

Change-Id: I65ffbfd7db99f45fc0310c7239bdfc0522c65e3a