Adds HubUtility to resolve hub names.

[JRWinter1]

Keeps HubContext name resolution consistent with OrleansHubLifetimeManager.

I understand this could be breaking to some consumers of the library. However, I thought Id' raise the PR to get the conversation going.

In my opinion, the OrleansHubLifetimeManager should not look for the typed client of the hub when resolving the hub name but maybe I am missing something.

I've also brought the HubContext in line with the actual implementation of hub context which will ensure consistency between the HubContext and OrleansHubLifetimeManager.

From MSDN:
public interface IHubContext<out THub> where THub : Hub
Ref:
https://docs.microsoft.com/en-us/dotnet/api/microsoft.aspnetcore.signalr.ihubcontext-1?view=aspnetcore-6.0

[JRWinter1]

It would be nice to support strongly typed HubContext too:

public interface IHubContext<THub,T> where THub : Hub<T> where T : class

But that is a separate piece of work and slightly more involved so I will try to pick up in the near future.

[galvesribeiro]

Thanks @JRWinter1. Makes total sense. Since this is an internal thing, it should not be a breaking change as nobody should be relying on it. Nonetheless, I'll merge it as part of the v7.

Thanks!