Refine subject input for PDPInput and PolicyInput

[Dirklectisch]

The subject input for the PDP needs to be changed so that:

• Like with the Request and Context attributes Subject should not have a nested properties element
• Instead the subject should directly take the introspected token data
• Three prefixes should be used for the token attributes
  • client_ for information about the application
  • organization_ for information about the organisation subject
  • user_ for information about the user subject like the employee

The PDP should parse this input and nest the three prefixes above properly in the PolicyInput instead of having a bag of properties.