Fixes to log output lines and log setup

[franklywatson]

Log lines were not being output to JSON the same way as they were being output to stdout so needed to adjust the way logged values were being stringified.

Also removed the --log-output option to always use stdout since it gets confusing when looking at server logs in grafana which show both stdout and stderr; want to keep clean separation between them

[m-Peter]

The body["result"] is not always a container value (e.g. an array or map). It can also be a scalar value, e.g.

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x2"
}

So the Fields will not work for this case.

[m-Peter]

@franklywatson Here is the end result of how logs will look like:

API request log line:

{
    "level": "debug",
    "component": "API",
    "url": "/",
    "id": 10,
    "method": "eth_syncing",
    "params": [],
    "is-ws": false,
    "time": "2024-03-11T18:37:27+02:00",
    "message": "API request"
}

API response with boolean result:

{
    "level": "debug",
    "component": "API",
    "id": 10,
    "result": false,
    "time": "2024-03-11T18:37:27+02:00",
    "message": "API response"
}

API response with string result:

{
    "level": "debug",
    "component": "API",
    "id": 1,
    "result": "0xe414f90fea2aebd75e8c0b3b6a4a0c9928e86c16ea724343d884f40bfe2c4c6b",
    "time": "2024-03-11T18:48:05+02:00",
    "message": "API response"
}

API response with null result:

{
    "level": "debug",
    "component": "API",
    "id": 7,
    "result": null,
    "time": "2024-03-11T18:38:50+02:00",
    "message": "API response"
}

API response with dictionary result:

{
    "level": "debug",
    "component": "API",
    "id": 7,
    "result": {
        "hash": "0x1c501d129b02678731e97461ee37ba69b7b1f76cb0e69599aecd2c05d309294f",
        "number": "0x2",
        "parentHash": "0x0e67c87db388a7ac0ce4922ccc225793fa93cf6b701ae28c3654b2c1ab780924",
        "receiptsRoot": "0x0000000000000000000000000000000000000000000000000000000000000000",
        "transactions": [
            "0x1063764dc57cbc6c73051a74d593efd40c6e0999ba05003de631d7ce10806808"
        ]
    },
    "time": "2024-03-11T18:38:33+02:00",
    "message": "API response"
}

API response with error:

{
    "level": "debug",
    "component": "API",
    "error": {
        "code": -32602,
        "message": "invalid argument 0: hex string without 0x prefix"
    },
    "id": 7,
    "time": "2024-03-11T18:39:18+02:00",
    "message": "API response"
}

[franklywatson]

Looks great thanks!