refactor(flow)!: Use watcher to change every prop as a single item

* instead of replacing the whole state on each watch trigger, split into multiple watchers that set a single state
* improve reacitivty and two-way binding for v-models
* remove elements option -> only modelValue (old api) or nodes/edges

Signed-off-by: Braks <78412429+bcakmakoglu@users.noreply.github.com>

src/types/node.ts

@@ -62,13 +62,12 @@ export interface NodeProps<T = any> {
     source?: HandleElement[]
     target?: HandleElement[]
   }
-  // todo plugin not allowing for nested types currently
-  parentNode?: any
+  parentNode?: GraphNode[]
   isParent?: boolean
   computedPosition: XYZPosition
   position: XYPosition
   draggable?: boolean
   selectable?: boolean
-  children?: any[]
+  children?: Node[]
   dimensions?: Dimensions
 }