[Feature request] Pinch to zoom gesture in Remote view (Quick, Widgets) and Textures

Some time ago it became possible to have hi-res scrolling, pinch and swipe gestures with libinput on Linux, even under X11. Firefox (although based on GTK) is a great example of an application which uses them to the fullest, including inertial scrolling.

It should be possible (however, might be not in Qt 5) to handle pinch gestures from a touchpad to zoom in and out of a Remote view — both for QtQuick scenes and QtWidgets — as well as for the Texture tab. There may be other zoomable views in GammaRay which I'm missing, but the idea is that all of them should eventually be zoomable with gestures.