CGMES IDs persistence after export

[miovd]

• Do you want to request a feature or report a bug?
  Neither, it is a pending question.

• What is the current behavior?
  After a CGMES export, a lot of information are kept inside the IIDM network (), which can be detrimental to performances and the use of this is relative.

• What is the expected behavior?
  Maybe we could make keeping generated CGMES information optional?

• Please tell us about your environment:

  • PowSyBl Version: 4.8.0-SNAPSHOT