Provide QML import paths to androiddeployqt

Summary:
This makes the qmlimportscanner find our QML files and plugins correctly.
That's IMHO much cleaner than the full copy of everything in the lib/qml
folder we do via the android-extra-plugins list.

Reviewers: Build System, apol

Reviewed By: apol

Subscribers: Frameworks

Tags: Frameworks, Build System

Differential Revision: https://phabricator.kde.org/D11177