`D` adds a new Domain for DNSControl to manage. The first two arguments are required: the domain name (fully qualified `example.com` without a trailing dot), and the
name of the registrar (as previously declared with [NewRegistrar](#NewRegistrar)). Any number of additional arguments may be included to add DNS Providers with [DNSProvider](#DNSProvider),
add records with [A](#A), [CNAME](#CNAME), and so forth, or add metadata.
Modifier arguments are processed according to type as follows:
- A function argument will be called with the domain object as it's only argument. Most of the [built-in modifier functions](#domain-modifiers) return such functions.
- An object argument will be merged into the domain's metadata collection.
- An array argument will have all of it's members evaluated recursively. This allows you to combine multiple common records or modifiers into a variable that can