[TIMOB-24517] Android: Add APK signature scheme v2 support

*Summary:* Titanium currently only supports signing with v1 signature scheme. We should add v2 signing support, which can be verified on Android 7.0 and higher. https://source.android.com/security/apksigning/v2 Note that an APK can be signed by both v1 and v2 at the same time. We still need v1 support for Android OS versions older than 7.0. *Note 1:* This can be signed manually via Android SDK build tool "apksigner". https://developer.android.com/studio/command-line/apksigner *Note 2:* The "gradle" build system automatically signs all built APKs with both v1 and v2. When we add "gradle" build support, then we get v2 signing for free. *Testing:* You can verify which versioning schemes an APK has been signed with at the command line by doing the following...

Open the Mac "Terminal".

CD to directory: ~/Library/Android/sdk/build-tools/<NewestVersion>

Enter: ./apksigner verify -v <PathToApk>

The tool will output something like the below. Make sure v2 is flagged true.

Verified using v1 scheme (JAR signing): true
Verified using v2 scheme (APK Signature Scheme v2): true
Verified using v3 scheme (APK Signature Scheme v3): false