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/flow.ts

@@ -85,7 +85,6 @@ export interface FlowProps<N = any, E = N> {
   modelValue?: any[]
   nodes?: Node<N>[]
   edges?: Edge<E>[]
-  elements?: Elements
   id?: string
   connectionMode?: ConnectionMode
   connectionLineType?: ConnectionLineType