[resource-manager] update the resolveArmResources to support the "multiple singleton resource pattern"

[ArcturusZhang]

We could assign type to a resource's name by a string union (extensible enum) or an enum (a fixed enum), in this case, the resource should be considered as multiple instances of singleton resources.
The API of resolveArmResources should return it.

[markcowl]

@ArcturusZhang I think the mechanism we use to indicate a singleton is the singleton name array returned with the resource, is that what you had in mind, or was there something else?