Add custom Rich Presence names

[JustArion]

Discord normally discards the Name property and replaces it with the name associated with the Discord Application. Projects such as arRPC from OpenAsar are more lenient on such restrictions. Clients using OpenAsar will have their Discord Rich Presence shown like the screenshot below if the commit is merged.

Normal Discord clients are unaffected by this change and modifying the property will do nothing for them (for now).

If the user has a normal Discord client:

Confirmed working with arRPC via the BasicExample

            client.SetPresence(new RichPresence()
            {
                Name = "A test Example",
                Details = "A Basic Example",
                State = "In Game",
                Timestamps = Timestamps.FromTimeSpan(10),
                Buttons = new Button[]
                {
                    new Button() { Label = "Fish", Url = "https://lachee.dev/" }
                }
            });

Client running openAsar:

The PR is similar to #255 though currently only targets openAsar users. Discord will probably allow this in the default client in the future.

Fixes #48