Change default for nsec3param to iterations 0 salt-length 0

Following the guidance given in https://datatracker.ietf.org/doc/draft-ietf-dnsop-nsec3-guidance/

   In short, for all zones, the recommended NSEC3 parameters are as
   shown below:

   ; SHA-1, no extra iterations, empty salt:
   ;
   bcp.example. IN NSEC3PARAM 1 0 0 -