Include a "list type" information in the Contingency List JSON representation.

[tadam50]

• Do you want to request a feature or report a bug?
  Feature

• What is the current behavior?
  Contincency list JSON representation do not contains version & type information

• What is the expected behavior?
  Add versioning information and use JSON annotation "@c"

• What is the motivation / use case for changing the behavior?
  Otherwise, if we add other types later (think CountryList for example), we may have some issues to deserialize old files.

• Please tell us about your environment:

  • PowSyBl Version: ...
  • OS Version: ...

• Other information (e.g. detailed explanation, stacktraces, related issues, suggestions how to fix, links for us to have context, eg. stackoverflow, spectrum, etc)

Originally posted by @sylvlecl in #925 (comment)