Add anyhow-inspired error utilities

[jprendes]

This pull request adds a set of ergonomic error handling utilities to the src/hyperlight_guest/src/error.rs module, making it easier to attach context and custom error codes to errors in guest code. The changes include a new trait for contextual error conversion, implementations for Option and Result, two macros for concise error handling, and comprehensive unit tests to ensure correct behavior.

Error handling improvements:

• Added the GuestErrorContext trait, which allows attaching context and error codes to Option and Result types, making it easier to convert them into rich error types (HyperlightGuestError).
• Implemented GuestErrorContext for both Option<T> and Result<T, E>, enabling context-aware error conversion for these types.

Convenience macros for error handling:

• Introduced the bail! macro to immediately return an error with a message and optional error code, and the ensure! macro to assert conditions and return errors if the condition fails.

Testing and validation:

• Added a suite of unit tests that thoroughly verify the behavior of the new trait implementations and macros, ensuring reliability and correctness.

[simongdavies]

LGTM