resolvectl: add print_configuration() to consolidate status logic

resolvectl: add print_configuration() to consolidate status logic

There is a lot of duplication across the functions for printing global,
link, and delegate output. Since these all use a common DNSConfiguration
type now, the logic can be consolidated.

Adapt printing and format helper functions to accept a DNSConfiguration
parameter to appropriately format output. Then, add print_configuration(),
a single function that prints the appropriate status output based on the
contents of DNSConfiguration.