Add an OpenRPC Document

[Nana-EC]

Problem

We currently don't have complete documentation for the endpoints provided

Solution

We should utilize the OpenRPC standard and the OpenRPC Playground

• Create an OpenRPC compliant spec in the repo
• Note the spec in the main README with a link to the playground to view it e.g. https://playground.open-rpc.org/?schemaUrl={repoSchemaUrl}
• Add a test case to validate spec and ensure compliance - see Open RPC Schema Test example

See Open RPC examples and OpenRPC in the wild for notable examples

Alternatives

No response

[ar-conmit]

The ticket has some progress in this branch. The following methods are already documented:
eth_getBlockByHash
eth_getBlockByNumber
eth_getBlockTransactionCountByHash
eth_getBlockTransactionCountByNumber
eth_getUncleCountByBlockHash
eth_getUncleCountByBlockNumber
eth_protocolVersion
eth_chainId
eth_syncing
eth_coinbase
eth_accounts
eth_blockNumber

[Nana-EC]

Great work.
If possible please update server.ts to serve the document up, so it's available for every deployment.