Add minimum tx fee to rosetta construction/metadata

[jspada]

This PR adds the minimum tx fee to the rosetta construction/metadata response so that clients can prevent users from creating transactions that would fail to be accepted. The minimum fee is obtained from the compile-time config Mina_compile_config.minimum_user_command_fee

For compatibility with the Rosetta specification we've added the additional "minimum_fee" information to the metadata property like so

{
    "metadata": {
        "sender": "B62qnzbXmRNo9q32n4SNu2mpB8e7FYYLH8NmaX6oFCBYjjQ8SbD7uzV",
        "nonce": "0",
        "token_id": "1",
        "minimum_fee": [
            {
                "value": "1000000",
                "currency": {
                    "symbol": "CODA",
                    "decimals": 9
                }
            }
        ]
    },
    "suggested_fee": [
        {
            "value": "250000000",
            "currency": {
                "symbol": "CODA",
                "decimals": 9
            }
        }
    ]
}

Testing
This can be tested with mina_ledger_wallet send-payment and src/app/rosetta/test-curl/con_metadata.sh. Prior to this change the "minimum_fee" component will not be present in the JSON response. After this change it should be present and contain the value found in src/config/amount_defaults/realistic.mlh.

Checklist:

• Document code purpose, how to use it
  • Mention expected invariants, implicit constraints
• Tests were added for the new behavior
  • Document test purpose, significance of failures
  • Test names should reflect their purpose
• All tests pass (CI will check this if you didn't)
• Serialized types are in stable-versioned modules
• Does this close issues? List them:

Closes #8086

[jspada]

New format as suggested by Matthew and Brandon is

{
    "metadata": {
        "sender": "B62qnzbXmRNo9q32n4SNu2mpB8e7FYYLH8NmaX6oFCBYjjQ8SbD7uzV",
        "nonce": "0",
        "token_id": "1"
    },
    "suggested_fee": [
        {
            "value": "250000000",
            "currency": {
                "symbol": "CODA",
                "decimals": 9
            },
            "metadata": {
                "minimum_fee": {
                    "value": "1000000",
                    "currency": {
                        "symbol": "CODA",
                        "decimals": 9
                    }
                }
            }
        }
    ]
}

[mrmr1993]

Great!

[bkase]

OCaml master

[jspada]

Getting there... and thanks to help from Matthew and Omer.

[bkase]

!approved-for-mainnet

[mrmr1993]

!ci-build-me