feat(react/svelte): controlled viewport (#3461)

* feat(react): controlled viewport

* refactor(react): cleanup viewport

* feat(svelte): two way data binding for viewport, cleanup transform <> viewport stuff

* refactor(svelte): viewport stuff

packages/svelte/src/lib/container/Zoom/Zoom.svelte

@@ -20,7 +20,7 @@
   export let panOnScroll: $$Props['panOnScroll'];
 
   const {
-    transform,
+    viewport,
     panZoom,
     selectionKeyPressed,
     minZoom,
@@ -38,7 +38,7 @@
 <div
   class="svelte-flow__zoom"
   use:zoom={{
-    transform,
+    viewport,
     minZoom: $minZoom,
     maxZoom: $maxZoom,
     initialViewport: viewPort,