[dns-server] reorganize per RFD 619#9483

sunshowers merged 11 commits intomainoxidecomputer/omicron:mainfrom

sunshowers/spr/rfc-dns-server-move-to-new-code-organization-defined-in-rfd-619oxidecomputer/omicron:sunshowers/spr/rfc-dns-server-move-to-new-code-organization-defined-in-rfd-619Copy head branch name to clipboard