Refactor Storage to decide which serializer/deserializer for IndexEdge/SnapshotEdge/Vertex.

SerDe for IndexEdge/SnapshotEdge/Vertex works differently based on label's schemaVersion and Storage only use one SerDe pair for each ones now.

Decision for which SerDe is used for each label should be controlled by Storage since some of storage implementation only use certain SerDe pair for every label schema version.

The only reason we can't truncate schema v1, v2 is only for backward compatibility.

I am suggesting moving logic to decide which SerDe when given label's schemaVersion from IndexEdge/SnapshotEdge SerDe to Storage so newly added storage implementation override this logic to avoid manually change test label`s schema version, since some of newly added storage implementation only support some of schema version.