disable checks by default in named-compilezone

Zone content integrity checks can significantly slow the conversion of zones from raw to text. As this is more properly a job for named-checkzone anyway, we now disable all zone checks by default in named-compilezone.

Users relying on named-compilezone for integrity checks as well as format conversion can run named-checkzone separately, or re-enable the checks in named-compilezone by using: "named-compilezone -n fail -k fail -r warn -T warn -W warn".

Closes #4364 (closed)