AAPT2: Embed version of framework an app was compiled against.

This change injects the 'android:compileSdkVersion' and
'android:compileSdkVersionCodename' into an app's AndroidManifest.xml,
whose values are dervied from the version name and version code of the
framework AndroidManifest.xml that is being linked against.

Bug: 63388434
Test: make aapt2_tests
Change-Id: I7b607192ecb337307c4bcb5770e7f716c6d4c9d2