UPDATE role

Should implement the API as specified in the spec

Implementation notes (use as guidelines and reach out to sgunta@redhat.com if you run into issues implementing):

View:

• should update http_method_names in the view, to include PUT
• Add a separate method for update in the view (similar to create)

Serializer

• Reuse the RoleV2RequestSerializer and RoleV2ResponseSerializer, since the request and response should be pretty similar
• Keep this layer as minimal as possible, avoid adding any validations

Service

• Add new method for update
• It should be enclosed in the @atomic decorator
• You should look up an existing role and throw an exception if it does not exist. A new exception may need to be added here.
• Refactor common code from create and reuse here as much as possible
• Replication should happen successfully, so write needs to be made to outbox

Acceptance Criteria:

• API spec should take implementation into consideration
• API should be consistent with other RBAC V2 APIs
• Shared in the team-mgmt-fabric channel and reviewed by architects and leads
• Have to consider this: https://issues.redhat.com/browse/RHCLOUD-37863
  • For implementing Serializable isolation, we introduced an @atomic decorator and a mixin to apply this across all APIs in a given namespace
  • Use the same pattern. The mixin may need to be updated to work for batch delete method
  • Something to note is that the decorator for an atomic transaction should be in the service layer method as well as the view.
• Should follow hexagonal architecture principles. The attached diagram is a good reference of how to organize concerns between layers. Please use the CreateRole PR as a reference. 
• Tests should be implemented for each layer