JSON-RPC Discovery Support

## Details
I think this project could benefit from integration with OpenRPC which provides a base foundation for service discovery and tooling such as documentation/client generation/mock server for JSON-RPC akin to OpenAPI/Swagger.

Here is an example of an ethereum node with the OpenRPC playground, it gets the OpenRPC Document via calling the [rpc.discover](https://spec.open-rpc.org/#service-discovery-method) method:

https://playground.open-rpc.org/?url=https://services.jade.builders/core-geth/mainnet/1.11.2

and just the bare inspector:
https://inspector.open-rpc.org/?url=https://services.jade.builders/core-geth/mainnet/1.11.2

Let me know how I can help.

The issue proposes adding OpenRPC-based discovery and tooling for this project's JSON-RPC services, but names no files, tests, or entry points. First map the existing JSON-RPC implementation and determine the required discovery and OpenRPC document scope; done would mean an agreed implementation plan and corresponding support for the proposed tooling.

Written by the indexing model from the issue text.