Split APK by each target in order to reduce size

The APK was ~ 6MB before we introduced `arklib` into the project:
https://github.com/ARK-Builders/ARK-Shelf/actions/runs/2711988751

Now it is 50MB:
https://github.com/ARK-Builders/ARK-Shelf/actions/runs/2905621288

I think we can do the same split build as in [ARK Navigator](https://github.com/ARK-Builders/ARK-Navigator).

Compare the two linked ARK Shelf GitHub Actions runs with ARK Navigator's split-build setup, since no project files are named in the issue. Done means the Android build produces a separate APK for each target and the resulting APK sizes are reduced from the current ~50 MB.

Written by the indexing model from the issue text.