Change output of events in logs from Rust debug to JSON

[leighmcculloch]

What

Change the output of contract events in logs from successful invocations from Rust debug to XDR and JSON.

Before

❯ stellar contract invoke --id $(stellar contract asset id --asset native) -- transfer --from me --to you --amount 1
2024-09-11T23:51:12.556972Z  INFO contract_event: soroban_cli::log::event: 1: DiagnosticEvent {
    in_successful_contract_call: true,
    event: ContractEvent {
        ext: V0,
        contract_id: Some(
            Hash(d7928b72c2703ccfeaf7eb9ff4ef4d504a55a8b979fc9b450ea2c842b4d1ce61),
        ),
        type_: Contract,
        body: V0(
            ContractEventV0 {
                topics: VecM(
                    [
                        Symbol(
                            ScSymbol(
                                StringM(transfer),
                            ),
                        ),
                        Address(
                            Account(
                                AccountId(
                                    PublicKeyTypeEd25519(
                                        Uint256(309d08c0d6e866993dfb33067291149d652b1ca75b690853b52a042b2947b1f5),
                                    ),
                                ),
                            ),
                        ),
                        Address(
                            Account(
                                AccountId(
                                    PublicKeyTypeEd25519(
                                        Uint256(7ac81d6ba7f93d9d17f226499d7df794f9ecd45c842f1e045aff9591e61c46d9),
                                    ),
                                ),
                            ),
                        ),
                        String(
                            ScString(
                                StringM(native),
                            ),
                        ),
                    ],
                ),
                data: I128(
                    Int128Parts {
                        hi: 0,
                        lo: 1,
                    },
                ),
            },
        ),
    },
}

After

❯ stellar contract invoke --id $(stellar contract asset id --asset native) -- transfer --from me --to you --amount 1
2024-09-12T00:00:01.671960Z INFO contract_event: soroban_cli::log::event: 1: AAAAAQAAAAAAAAAB15KLcsJwPM/q9+uf9O9NUEpVqLl5/JtFDqLIQrTRzmEAAAABAAAAAAAAAAQAAAAPAAAACHRyYW5zZmVyAAAAEgAAAAAAAAAAMJ0IwNboZpk9+zMGcpEUnWUrHKdbaQhTtSoEKylHsfUAAAASAAAAAAAAAAB6yB1rp/k9nRfyJkmdffeU+ezUXIQvHgRa/5WR5hxG2QAAAA4AAAAGbmF0aXZlAAAAAAAKAAAAAAAAAAAAAAAAAAAAAQ== {"in_successful_contract_call":true,"event":{"ext":"v0","contract_id":"d7928b72c2703ccfeaf7eb9ff4ef4d504a55a8b979fc9b450ea2c842b4d1ce61","type_":"contract","body":{"v0":{"topics":[{"symbol":"transfer"},{"address":"GAYJ2CGA23UGNGJ57MZQM4URCSOWKKY4U5NWSCCTWUVAIKZJI6Y7KL63"},{"address":"GB5MQHLLU74T3HIX6ITETHL566KPT3GULSCC6HQELL7ZLEPGDRDNS5OC"},{"string":"native"}],"data":{"i128":{"hi":0,"lo":1}}}}}}

Why

The rust debug is less human readable than JSON, because the Rust debug representation of the XDR types outputs values like the contract ID Hash, instead of the C string.

The output format has attempted to be as similar as possible to the output that @BlaineHeffron is using in:

• Feature: Adds logging for DiagnosticEvents that are emitted during simulation  #1499

Close #1447