Management framework: add get_configuration_request/response transaction

Includes submodule bumps for Broker (to pull in better handling of data
structures that are difficult to unserialize in Python), zeek-client (for the
get-config command), and a commit hash update for the external testsuite.

auxil/broker

@@ -1 +1 @@
-Subproject commit 9f2f16c1da94b03790bc8b9f69bc2688e97b781f
+Subproject commit 18b070fe1e8f9e141da2a8393779abc5e4fca886

auxil/zeek-client

@@ -1 +1 @@
-Subproject commit a08d9978ac6ff6481ad1e6b18f0376568c08f8c1
+Subproject commit b443dd4e098ea4d70771940515cf7833de29b325

scripts/policy/frameworks/management/controller/api.zeek

@@ -57,6 +57,27 @@ export {
 	    result: Management::ResultVec);
 
 
+	## zeek-client sends this event to retrieve the currently deployed
+	## cluster configuration.
+	##
+	## reqid: a request identifier string, echoed in the response event.
+	##
+	global get_configuration_request: event(reqid: string);
+
+	## Response to a get_configuration_request event. The controller sends
+	## this back to the client.
+	##
+	## reqid: the request identifier used in the request event.
+	##
+	## result: a :zeek:see:`Management::Result` record with a successful
+	##     :zeek:see:`Management::Configuration` in the data member, if
+	##     a configuration is currently deployed. Otherwise, a Result
+	##     record in error state, with no data value assigned.
+	##
+	global get_configuration_response: event(reqid: string,
+	    result: Management::Result);
+
+
 	## zeek-client sends this event to request a list of
 	## :zeek:see:`Management::NodeStatus` records that capture
 	## the status of Supervisor-managed nodes running on the cluster's

scripts/policy/frameworks/management/controller/main.zeek

@@ -495,6 +495,30 @@ event Management::Controller::API::set_configuration_request(reqid: string, conf
 	check_instances_ready();
 	}
 
+event Management::Controller::API::get_configuration_request(reqid: string)
+	{
+	Management::Log::info(fmt("rx Management::Controller::API::get_configuration_request %s", reqid));
+
+	local res = Management::Result($reqid=reqid);
+
+	if ( is_null_config(g_config_current) )
+		{
+		# We don't have a live configuration yet.
+		res$success = F;
+		res$error = "no configuration deployed";
+		}
+	else
+		{
+		res$data = g_config_current;
+		}
+
+	Management::Log::info(fmt(
+	    "tx Management::Controller::API::get_configuration_response %s",
+	    Management::result_to_string(res)));
+	Broker::publish(Management::Controller::topic,
+	    Management::Controller::API::get_configuration_response, reqid, res);
+	}
+
 event Management::Controller::API::get_instances_request(reqid: string)
 	{
 	Management::Log::info(fmt("rx Management::Controller::API::set_instances_request %s", reqid));

testing/external/commit-hash.zeek-testing-cluster

@@ -1 +1 @@
-1b515f3f60abed5c505a970cae380560ce6304c1
+e992af6c5b7b6416cd34c43f1d003227f303a72e