Support files for the uacme(1) and certbot(1) ACMEv2 clients

	nsupdate.sh	POSIX compliant uacme(1) hook script for the dns-01
			challenge type with CNAME and DNAME support
	nsupdate.conf	nsupdate.sh configuration file
	500.uacme	periodic(8) script to automatically renew certificates
			using uacme(1)
	cleanup.sh	certbot(1) manual cleanup hook script
	authenticator.sh certbot(1) manual auth hook script

It is best practice to create a separate zone for the ACME challenge.

	zone "_acme-challenge.example.com" {
		type primary;
		file "_acme-challenge.example.com";
		dnssec-policy default;
		inline-signing yes;
		update-policy {
			grant tsig-key zonesub TXT;
		};
	};

The following records in the parent zone would redirect the ACME challenge to
the dedicated ACME challenge zone.

	$ORIGIN example.com.
	_acme-challenge	3600	DS	; see dnssec-dsfromkey(1)
				NS	ns1
				NS	ns2
	_acme-challenge.www	CNAME	www._acme-challenge