the utility supports most of the 'unbound-host'
functionality except PTR records

this is a boilerplate for a CLI utility to resolve
names and execute script on query response
in another words, "a jq for resolver answers"

this is a scaffolding for alternative tools like
'host' or a plug-in part for scripting around it.

it basically starts a kresd instance, but doesn't
bind to any interface or read configuration,
then a query + callback is sent to kresd standard
input, and it quits after the execution