docs(backlog): Document source mapper include_block_cbor argument

[mark-stopka]

Documentation was not updated with the #127

PR #127 implements an optional flag that will include the raw cbor payload for each block as a extra field of the Block event. To enable the feature, the include_block_cbor flag of the mapper config needs to be enabled. The following is an example of a daemon mode config that includes the payload and outputs to the stdout sink:

[source]
type = "N2N"
address = ["Tcp", "relays-new.cardano-mainnet.iohk.io:3001"]
magic = "mainnet"
since = [19284008, "c91204d1ea48281023147416851008c192dbf7e4dba9c89597c715fa0af68939"]

[source.mapper]
include_block_cbor = true

[[filters]]
type = "Selection"

[filters.check]
predicate = "variant_in"
argument = ["Block"]

[sink]
type = "Stdout"
format = "JSONL"

This is an example of the output:

{
    "block": {
        "body_size": 1094,
        "cbor_hex": "820384828f1a004fa3be1a012640625820c04e0a42caf9947b8edcb208e41f6ee130b7446... [REDACTED]",
        "hash": "586f3c5dff0a9a026b04b183b1923da6d5181270d1362d073725f044aa5460d7",
        "issuer_vkey": "61261a95b7613ee6bf2067dad77b70349729b0c50d57bc1cf30de0db4a1e73a8",
        "number": 5219262,
        "previous_hash": "c04e0a42caf9947b8edcb208e41f6ee130b7446c76872fe9af5ed33067092590",
        "slot": 19284066,
        "tx_count": 3
    },
    "context": {
        "block_hash": "586f3c5dff0a9a026b04b183b1923da6d5181270d1362d073725f044aa5460d7",
        "block_number": 5219262,
        "certificate_idx": null,
        "input_idx": null,
        "output_address": null,
        "output_idx": null,
        "slot": 19284066,
        "timestamp": 1610850357,
        "tx_hash": null,
        "tx_idx": null
    },
    "fingerprint": "19284066.blck.310275953652163912797886047039773707901"
}