Split part of www/qt5-websockets into new port www/qt5-websockets-qml

This splits qt5-websockets into a qt5-websockets port containing the core parts,
and a qt5-websockets-qml port with the QML parts. The QML parts depend on Qt Quick,
so on the GUI parts (and hence X11) while the core parts do not.

PR: 220045
Submitted by: Adriaan de Groot <groot@kde.org>