Optimize Android build

[DiligentGraphics]

There are a number of issues with Android build now:

• All shared projects in Common are built for every executable target (sample, tutorial, etc.). This makes the build super slow
• .so of all executable targets are packed in every APK
• Incremental build is super slow. In fact, trying to run an app from Android studio takes few minutes even if there were no changes because a number of projects are rebuilt no matter what

[DiligentGraphics]

Update: after switching to using NDK from Android Studio (as recommended), the excessive build and incremental build problems seem to be fixed.

[DiligentGraphics]

Using build flavors in gradle allows packaging only needed .so files into the APK, however, causes the entire native part to be built for every Android application.

[DiligentGraphics]

https://stackoverflow.com/questions/58574110/android-build-select-which-libraries-to-package-from-a-dependency-project