Support Multitouch gestures in guests

I would love to have some gesture support on my virtual machine. Nowadays, especially having a Mac I (and I suspect many others) am/are so accustomed to those once fancy features such as pinch to zoom, but also multi-finger swipes and so on. Especially as many linux distributions (and windows for a while) now [start to offer true gesture navigation](https://blog.elementary.io/multitouch-gestures-in-elementary-os-6/) (no shortcut assigning) this would be a welcome feature. [A quick web-search lead me to believe](https://github.com/aosp-mirror/platform_external_qemu/blob/master/android/multitouch-screen.h) there has been done some QEMU-specific gesture pass-through work, which already had been useful for mobile app development/testing.

It would be great to get some community echo and especially some developer feedback on this.