processgroup: Set min_sdk_version

Modules contributing mainline modules (APK/APEX) should set
min_sdk_version as well as apex_available.

For now setting min_sdk_version doesn't change build outputs.
But build-time checks will be added soon.

Bug: 152655956
Test: m
Merged-In: Idaa27ce24cc13d13145eaef85a08b9033922c7bc
Change-Id: Idaa27ce24cc13d13145eaef85a08b9033922c7bc
(cherry picked from commit 4f55f3ef)