Create System.Text.Json.Nodes.JsonValue for non-generic number

[Joy-less]

Hi, I'm wondering if there's a way to efficiently create a JsonNode for a number from a string.

JsonValue.Create(int); // Doesn't support integers that don't fit in Int32 or Int64.
JsonValue.Create(intAsString); // Creates a string token rather than a number token.
JsonNode.Parse(intAsString); // Not efficient since the number has to be re-parsed. Plus, doesn't support numbers like ".2" which are parsed fine by `double.Parse` but not as JSON.

My use case is a stream for JSON/HJSON tokens: https://github.com/Joy-less/HjsonSharp

[Joy-less]

API proposal: #111548