Introduce the sharedUserMaxSdkVersion attribute

We need a mechanism to allow developers to opt-out of
shared UID without removing the android:sharedUserId
attribute to maintain compatibility with older Android
versions.

The developer can set the highest API level at which the
sharedUserId attribute will be recognized, analogous to
using maxSdkVersion in <uses-permission>.

Bug: 196261070
Test: build + flash + TH
Change-Id: I12d2bc0997d1291991b1289a7b0dda0d954f2bd2