DNS: dns import fixes, NAPTR support, TLSA and CAA in remote api.

This improves the DNS zone file importer, adds NAPTR record editor, and remote api function calls for TLSA and CAA records.

Fixes #5572 (closed). Fixes #2092 (closed). Fixes #4753 (closed). Fixes #5585 (closed). Fixes #4360 (closed). Fixes #5559 (closed). Fixes #5623 (closed).