Add targetOverlayableName to OverlayInfo

This change add information about the target overlayable to the
OverlayInfo class.

Bug: 128830059
Test: atest OverlayInfoTest
Test: cmd overlay dump
Test: overlays.xml generated correctly

Change-Id: Ice9b4dee20d7d5ea4dcbc2b1a1179ab4fa5b1f7a