IAM schema abstract constraints need review following abstract role update

[james-whiteside]

Description

There are a number of constraints in the IAM demo schema that could not be added easily without upcoming features, specifically the replacement of the abstract keyword with the @abstract annotation and the introduction of concrete roles to abstract relations. They will need to be made following the update, and are listed here:

Current	Updated
membership sub relation, abstract;	membership sub relation @abstract;
membership relates parent;	membership relates parent @abstract;
group membership relates group-member as member;	Remove line.
collection-membership relates collection-member as member;	Remove line.
set-membership relates set-member as member;	Remove line.
ownership sub relation, abstract;	ownership sub relation @abstract;
ownership relates owned;	ownership relates owned @abstract;
group-ownership relates group-owner as owner;	Remove line.
object-ownership relates object-owner as owner;	Remove line.
permission sub relation;	permission sub relation @abstract;
segregation-policy sub relation;	segregation-policy sub relation @abstract;