Refactor Resolver (support for mDNS and DoT)

[mrabine]

Description :

• Move away from the legacy Resolver class to a more flexible, template-based architecture.
• Allows for different transport layers (UDP, TLS, Multicast) while reusing the same DNS packet serialization/deserialization logic.
• Introduce BasicDnsClient to decouple DNS logic from the underlying socket type.
• Add transport policy class.
• Improve integration with the Reactor for non-blocking operations.