Support AAR files with androiddeployqt

I like to see support for AAR files created by androiddeployqt.
https://developer.android.com/studio/projects/android-library.html

We uses androiddeployqt to generate our APK files. Since it uses gradle it is possible to easily generate AAR files.
The build.gradle template needs to be adjusted a little bit. It has a hardcoded apply plugin: 'com.android.application". This must be replaced by "apply plugin: 'com.android.library'".

Also there are some tiny hardcoded stuff for APK in androideployqt that needs to be adjusted.

Of course we can use a custom build.gradle ourself. But official support would be great because it make it possible to easily distribute an SDK with native Qt libraries in it.