Support Qt 5.14 on Android

Summary:
Assets (QML files and icons) are no longer extracted into the file system,
but now are available in the android_rcc_bundle QRC file.

This is based on Francis' work mentioned in D26749, but slightly adjusted
to also fix icon loading as well.

Reviewers: mart

Reviewed By: mart

Subscribers: apol, plasma-devel

Tags: Kirigami

Maniphest Tasks: T12520

Differential Revision: https://phabricator.kde.org/D27525