Add an exported flag in manifest

With b/150232615, we will need an explicit value set for the exported
flag when intent filters are present, as the default behavior is
changing for S+. This change adds the value reflecting the previous
default to the manifest.

These changes were made using an automated tool, the xml file may be
reformatted slightly creating a larger diff. The only "real" change is
the addition of "android:exported" to activities, services, and
receivers that have one or more intent-filters.

Bug: 150232615
Test: TH
Exempt-From-Owner-Approval: mechanical refactoring
Change-Id: Iff9464db2b2cd04713a98489a097dd1570b9edf1