Move contributed DLZ modules into a separate repository

The DLZ modules are poorly maintained as we only ensure they can still
be compiled, the DLZ interface is blocking, so anything that blocks the
query to the database blocks the whole server and they should not be
used except in testing.  The DLZ interface itself should be scheduled
for removal.

lib/isc/include/isc/netaddr.h

@@ -28,7 +28,7 @@ ISC_LANG_BEGINDECLS
 
 /*
  * Any updates to this structure should also be applied in
- * contrib/modules/dlz/dlz_minmal.h.
+ * https://gitlab.isc.org/isc-projects/dlz-modules/-/raw/main/modules/include/dlz_minimal.h
  */
 struct isc_netaddr {
 	unsigned int family;

lib/isc/include/isc/sockaddr.h

@@ -25,7 +25,7 @@
 
 /*
  * Any updates to this structure should also be applied in
- * contrib/modules/dlz/dlz_minmal.h.
+ * https://gitlab.isc.org/isc-projects/dlz-modules/-/raw/main/modules/include/dlz_minimal.h
  */
 struct isc_sockaddr {
 	union {