- update gradle plugins versions
- add formatting rules for AndroidManifest and gradle build files
- cleanup java_godot_lib_jni
Note: logic was mostly moved around and no new logic/functionality was added.
The application module `app` serves double duties of providing the prebuilt Godot binaries ('android_debug.apk', 'android_release.apk') and the Godot custom build template ('android_source.zip').