eth: add official revert error code for call methods

[fjl]

Here I am trying to add an official way of getting the revert data of a contract call. This is often requested by users:

• Interface for errors RPC response in eth_call and eth_estimateGas #232
• eth_call underspecified return error message #463
• Standardise error response with error codes instead of strings for eth_sendTransaction, eth_sendRawTransaction and eth_estimateGas #523

The spec I'm adding here is what geth has been doing since 2022. It seems best to assign a separate error code because it's an unambiguous way of telling the error.

[ahamlat]

I suggest to have an error code similar to what we have on the engine API :

execution-apis/src/engine/common.md

Line 91 in 4140e52

| -32700 | Parse error | Invalid JSON was received by the server. |

Choose a close number like -31000

[fjl]

I'm using code 3 here because it is the error code used by geth and erigon for this condition.

There is no requirement for codes to be negative - the JSON-RPC spec says "The error codes from and including -32768 to -32000 are reserved for pre-defined errors. ... The remainder of the space is available for application defined errors."

[fjl]

I recently discovered MetaMask implements this spec change already.

[kclowes]

fwiw, this looks good to me. Would be nice to have this standardized across clients!