Make aapt2 dump badging print overlay info

This adds the contents of the manifest <overlay> tag to the
output of aapt2 dump badging.

Sample output:
  overlay: targetPackage='android' priority='1' isStatic='false'

Bug: 119938467
Test: aapt2 dump badging \
  $ANDROID_PRODUCT_OUT/vendor/overlay/framework-res__auto_generated_rro.apk
Change-Id: Ie9d904e6206ff8cf092744e630ee6f496672673c