Managed Identity tree view support

[nturinski]

Since we are adding more support to RBAC and managed identities, we should have more in-depth support for managed identity resources. It should include the following:

• A list of all the resources assigned to this managed identity
• A list of all the resources under the scope of this managed identity
• A list of all the role assignments within the scoped resources
• CRUD for managed identity
• CRUD for role assignments for the managed identity