Task - RBAC AuthZ - Modify role assignment endpoint for Admin Console

[rodmgwgu]

Related Discovery: https://openedx.atlassian.net/wiki/spaces/OEPM/pages/6060310529/Spike+-+M2+-+Endpoints+for+new+Admin+Console+designs

Modify the existing role assignment endpoint to sipport more than one scope at a time (bulk assign).

Spec:

PUT /api/authz/v1/roles/users/

• This endpoint already exists, but it only supports one scope at a time. We will need to add support for more than one scope at a time, but keep backwards compatibility.