ENSIP-6 Improvements

[buffrr]

This PR updates the status of ENSIP-6 from Stagnant to Draft and enhances compatibility with DNS without requiring changes to the DNS resolver profile. Instead, it establishes a better convention for translating ENS nodes and record sets to DNS.

The main improvement involves treating record sets as part of the top-level domain zone which may work better for .eth and enables several useful features:

• Nodes can delegate to a standard nameserver without coordinating with parent nodes by simply adding an NS record set.
• DNSSEC support is enabled through the use of DS record sets, effectively turning DNS into a secure layer 2 solution.
• CNAMEs can be added at the domain level, since domains are not at the zone apex (e.g., (nick.eth, nick.eth, CNAME)).
• Establishes a clearer relationship between record sets and ENS nodes.

This approach makes it theoretically possible to export all ENS nodes implementing this ENSIP into a DNS-compliant zone that can be consumed by standard DNS software with support for zone transfers ... etc.

There are other ways to do this, most come with their own trade-offs. This proposal does not require changing any contracts, but instead provides a clearer convention for those wanting to build DNS integrations for ENS but of course I'm open to other ideas. Thanks!