Added serde feature

[d-sonuga]

For dusk-network/rusk/issues/2773 and #414

[Neotamandua]

Looks good too. I just have the same comment as in another PR, whether we want to introduce so many custom error strings or just pass the underlying error through where applicable.

[Neotamandua]

Looks good in general. I would suggest using the same seed for randomness in the test cases.

Additionally, I think adding another test that checks the equality of a serialized struct against a serde_json string of an event is a good idea to make sure we have a test case that can catch if the attribute names of the struct ever change.

Example:

    #[test]
    fn event_fields() {
        let serde_json_string = "{\"source\":\"0000000000000000000000000000000000000000000000000000000000000000\",\"topic\":\"\",\"data\":\"\"}";
        let event = Event {
            source: ContractId::from_bytes([0; CONTRACT_ID_BYTES]),
            topic: String::new(),
            data: Vec::new(),
        };
        let ser = serde_json::to_string(&event).unwrap();
        assert_eq!(serde_json_string, ser);
    }

[miloszm]

Overall looks very good, just test fun rename seems important to me
for practical test usability

[miloszm]

LGTM