Add onion (#386)
Add onion (#386)

While "onion" does not appear within the root zone database, per RFC 7686, it is set aside as a special-use domain name, and explicitly called out as suitable for inclusion by IANA within the root zone database. Unlike other special-use domain names at this time, onion names that comply with RFC 7686 meet the definition of ICP-3 for both community process and a globally unique namespace (through being bound to keys in a process that ensures two clients end up with the same resolution).

Closes #374
sleevi/list,publicsuffix/list,sleevi/list,sleevi/list,rockdaboot/list,sleevi/list,publicsuffix/list,plinehan/list,publicsuffix/list,rockdaboot/list,plinehan/list,plinehan/list,publicsuffix/list,rockdaboot/list,rockdaboot/list