Remove thiserror

[sile]

Copilot Summary

This pull request includes several changes to error handling and error messages in the codebase. The most significant changes involve removing the thiserror dependency and implementing custom error formatting and conversion for various error types.

Error handling improvements:

• src/channel.rs: Removed thiserror dependency and added custom implementations for std::fmt::Display and std::error::Error for SendError and RecvError enums.
• src/epmd.rs: Removed thiserror dependency and added custom implementations for std::fmt::Display and std::error::Error for EpmdError enum.
• src/handshake.rs: Removed thiserror dependency and added custom implementations for std::fmt::Display and std::error::Error for HandshakeError enum.
• src/node.rs: Removed thiserror dependency and added custom implementations for std::fmt::Display and std::error::Error for NodeNameError enum.

Code simplification:

• src/handshake.rs: Introduced constants PROTOCOL_VERSION and NODE_NAME_VERSION to replace hardcoded values, improving code readability and maintainability. [1] [2] [3] [4]