Add RFC 9460 SVCB/HTTPS RR Type Support

Implement encoding and decoding for the SVCB (TYPE=64) and HTTPS (TYPE=65) resource record types defined in RFC 9460.

• Requires handling their specific RDATA structure: uint16 SvcPriority, TargetName (domain name), and a variable list of key-value SvcParams.
• Support for these types is important for modern service discovery (e.g., HTTP/3) and parameter negotiation (e.g., ECH). Requires careful parsing/generation of the SvcParams list.