Move Ctrl+wheel and trackpad pinch zoom into the Cesium renderer

installTrackpadPinchZoom and its pinch scaling move unchanged from
src/app/viewer.js to src/render/cesium/ctrlWheelZoom.js, where the input
port's ctrlWheelZoom will turn it on and off. The application scene
imports it from there; the application/viewer export no longer carries
this undocumented helper.

scripts/package-boundaries.json

@@ -2448,6 +2448,7 @@
       "src/app/surfaceServices.js",
       "src/app/tools.js",
       "src/app/viewer.js",
+      "src/render/cesium/ctrlWheelZoom.js",
       "src/sky/starrySky.js",
       "src/sky/stars.js",
       "src/app/atmosphereCompat.js",