Support the new Android App Bundles with androiddeployqt

Google announced the new "Android App Bundles" (aab) at Google I/O 2018 (See https://developer.android.com/guide/app-bundle/).

It would be nice if this was added to androiddeployqt sometime in the future.

Game plan:

• qmake needs to build any/all Android ABIs in one go.
• change some Qt Java bits to load specific ABI libs.
• change androiddeployqt to do all the magic for each ABI
• change androiddeployqt to package everything in one .aab
• change Qt for Android SDK layout:
  • libs folder will have an ABI subfolder libs/armeabi-v7a, libs/arm64-v8a,etc.
  • plugins same as libs
  • qml .so files, same as libs?