Oxidize exception `ProtocolError`

[FirelightFlagboy]

Todos

• [ ] Oxidize the python exception ProtocolError
• [ ] The ProtocolError in Rust can be created from:
  • [ ] ::rmp_serde::encode::Error (currently a string)
  • [ ] ::rmp_serde::decode::Error (currently a string)
  • [ ] std::num::TryFromIntError
• [ ] The ProtocolError in Python can be created from str

https://pyo3.rs/latest/function/error_handling.html#foreign-rust-error-types