Adapt TheaterShowtimesFetcher to work with Sailfish

-Use QWebPage instead of QWebView as we don't really need the view and
in Sailfish we don't have a widget.
-Use QUrlQuery for Qt5
-For Jolla Store we would something which completely does not rely on QtWidgets (i.e. QWebPage et al)
-Tested on Harmattan device and still works