Refactor android notification example to fit in qtbase. The example
demonstrates how to use JNI and work with Java APIs and add custom
Java code to a Qt app targeting Android.
Task-number: QTBUG-84382
Change-Id: I5fcbbf77b36eb47a0acaa13835ef3d773e63885c
Reviewed-by: Rami Potinkara <rami.potinkara@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Ville Voutilainen <ville.voutilainen@qt.io>
