move several query.c helper functions to client.c and rename

- these formerly static helper functions have been moved into client.c
  and made external so that they can be used in hook modules as well as
  internally in libns: query_newrdataset, query_putrdataset,
  query_newnamebuf, query_newname, query_getnamebuf, query_keepname,
  query_releasename, query_newdbversion, query_findversion
- made query_recurse() and query_done() into public functions
  ns_query_recurse() and ns_query_done() so they can be called from
  modules.

lib/ns/tests/query_test.c

@@ -91,7 +91,7 @@ run_sfcache_test(const ns__query_sfcache_test_params_t *test) {
 		test->cache_entry_flags == 0);
 
 	/*
-	 * Interrupt execution if query_done() is called.
+	 * Interrupt execution if ns_query_done() is called.
 	 */
 	ns_hook_t hook = {
 		.callback = ns_test_hook_catch_call,
@@ -292,7 +292,7 @@ run_start_test(const ns__query_start_test_params_t *test) {
 		 test->auth_zone_path != NULL));
 
 	/*
-	 * Interrupt execution if query_lookup() or query_done() is called.
+	 * Interrupt execution if query_lookup() or ns_query_done() is called.
 	 */
 	ns_hook_t hook = {
 		.callback = ns_test_hook_catch_call,