* first version dns_rcode0.sh
* fixed URLs for ACME calls
* fixed challenge remove
* read & write Token/URL at rm too
* make info messages debug
* typos fixed
* update rrset only if existing challenge is found
* polish error messages and make "detect root zone" scaleable
* fixed formating issues
* code cleanup, remove some unneeded functions
* removed empty lines
* save rcode0 url only if not default
