feat(format): Change the naming of vertex/edge type from `label` to `type`

[acezen]

Describe the enhancement requested

Since we plan to support multiple labels of vertex and edge. And currently we use the label as the unique type of vertex/edge, but it would make confusion with the multi-label in the future.

So it's better to make the type as the unique type of vertex/edge and let label be the multi-label.

Component(s)

Format

[Elssky]

I submitted this change

[acezen]

I submitted this change

Thanks for the contribution.