feat(store, flow)!: Add useNode/useEdge-state helpers

* for two way binding use the helpers

src/composables/useVueFlow.ts

@@ -106,6 +106,14 @@ export default (options?: FlowOptions): UseVueFlow => {
   const store = useStore(options)
   return {
     store,
+    useNodesState: (nodes) => {
+      store.setNodes(nodes)
+      return store.nodes
+    },
+    useEdgesState: (edges) => {
+      store.setEdges(edges)
+      return store.edges
+    },
     applyNodeChanges: (changes) => applyNodeChanges(changes, store.nodes),
     applyEdgeChanges: (changes) => applyEdgeChanges(changes, store.edges),
     ...store.hooksOn,