GaiaX 2411 compliant credentials: Participant, User, Administrator, Base/Envited-Membership

[jdsika]

resolves #6 #9 #17 #18 #19 #20

• Credential Types: Participant, User, Administrator, BaseMembership, EnvitedMembership
• Defining the "ASCS Administrator" we can add the membership information as a nested attribute. This will let users keep their credential as the participant will remain valid with a change of membership.
• Using the GaiaX 2411 definitions to align with the gx:LegalPerson and the gx:NaturalPerson (at least the name for now as now further definition exists)

[flhps]

I pushed updates to align the revocation entries with the VC Data Model 2.0 and my own work on CRSet. The context update should probably be validated, as I am not 100% sure everything is correct. The id field for the CRSetStatusEntry may need to be adjusted in the future, once we "officially" define independent contexts for that mechanism.

[jdsika]

closed for #24