Support use of Serde derive for fluvio protocol

[sehz]

It would be nice to use Serde for encoding/decoding fluvio protocol. The core encoder/encoder trait doesn't need to be changed; it's about writing Serde Serializer/Deserialize so we can leverage Serde procedure macro instead of maintaining our own. Tricky is to add support for Fluvio metadata, such as versions and default behavior.

So instead of this:

use fluvio_protocol::{Decoder, DecoderVarInt};
use serde::{Serialize,Deserialize}

#[derive(Encoder, Decoder, Default, Debug,Serialize,Deserialize)]
pub struct SimpleRecord {
    #[fluvio(min_version = 1)]
    len: i64,
    attributes: i8,
}

It can be written as this.

use fluvio_protocol::{Metadata};
use serde::{Serialize,Deserialize}

#[derive(Metadata, Default, Debug,Serialize,Deserialize)]
pub struct SimpleRecord {
    #[fluvio(min_version = 1)]
    len: i64,
    attributes: i8,
}

https://github.com/unegare/rust-notes/blob/master/serde-custom-derive-deserialize-synthetic-fields/src/main.rs
https://github.com/bincode-org/bincode/tree/trunk/src