feat(engine): Add JSON Web Token (JWT) token generation and validation support

[zerosnacks]

Motivation

Closes #599

Solution

Implements JSON Web Token utilities in the rpc-types-engine crate. Only focuses on JWT token generation and validation, not the auth layer as the generated token is used as a string in bearer auth.

Largely uses the JWT secret implementation by Reth with some enhancements to documentation and using built-in get_current_timestamp. Notably does not implement loading from file, reading from file or writing to file as that is out of scope for Alloy I feel.

Regarding the defined limitations on the algorithm and length, I've kept that 1:1 with the Reth implementation to make sure it can be used in that context and the limitations seem reasonable enough for a more general case.

See for reference: https://github.com/paradigmxyz/reth/blob/79452eadaf4963f1e8d78a18b1f490d7c560aa54/crates/rpc/rpc/src/layers/jwt_secret.rs

Proposed API:

let secret = JwtSecret::random(); or JwtSecret::from_hex(...)

let claims = Claims::default();
let jwt = secret.encode(&claims).unwrap();
let result = secret.validate(&jwt);

assert!(matches!(result, Ok(())));

Where Claims::default() is a claim defined as: Claim { iat: get_current_timestamp(), exp: None }

The random() syntax is consistent with other places that uses it (Address::random(), etc..)

PR Checklist

• Added Tests
• Added Documentation
• Breaking changes

[mattsse]

smol nit