add thumbstick teleport for Quest controllers

[micahstubbs]

something like this

        //
        // thumbstick teleport with Oculus Touch Controllers
        //

        //thumbstick Touched
        this.el.addEventListener('thumbsticktouchstart', function(e) {
          //Start pointing position to teleport
          this.emit('teleportstart')
        })

        //thumbstick Released
        this.el.addEventListener('thumbsticktouchend', function(e) {
          //Jump to pointed position
          this.emit('teleportend')
        })

[micahstubbs]

https://aframe.io/docs/0.9.0/components/oculus-touch-controls.html#events_thumbsticktouchstart

https://github.com/aframevr/aframe/issues/3928#issuecomment-450310831