Draft: DNS-over-HTTP support
This merge request completes the support for DNS-over-HTTP(S) built on top of
nghttp2 and plugs it into BIND. Support for both
requests is present, as required by RFC8484.
Both encrypted (via TLS) and unencrypted HTTP/2 connections are supported. The latter are mostly there for debugging/troubleshooting purposes and for the means of encryption offloading to third-party software (as might be desirable in some environments to simplify TLS certificates management).
Closes: #1144 (closed)