Should be forbiden explicit generation of system idtf

[smousy]

Is your feature request related to a problem? Please describe.
User or developer nowadays are able to create Russian system idtf using web or explicit generation with ScMemoryContext.CreateEdge(). But Russian system idtf should be forbidden.

Describe the solution you'd like
Need to forbid create edge from system idtf in web or explicit generation with ScMemoryContext.CreateEdge(). Only helper should be able to generate edge to system idtf.