This change modifies the policies for policy
association API to be more self-service by properly
checking for system scopes. It also includes the test cases.
Subsequent patches will -
- add domains user test coverage for policy association
- add project user test coverage for policy association
- Removing obsolete policies in policy.v3cloudsample.json file
Partial-Bug: #1805409
Change-Id: I7ed54a378dc20680cd987142c71afc36cb1dbd25