Add function to close HomeKit server

When performing a OTA firmware update, we need to shutdown the HomeKit sever because all network processing (including pings) stop during file uploads.  So system cannot process incoming TCP requests, risking out-of-memory crashes as buffers fill up.

Author: dkerr64

src/arduino_homekit_server.cpp

@@ -3559,6 +3559,16 @@ void arduino_homekit_setup(homekit_server_config_t *config) {
 	});
 }
 
+void arduino_homekit_close() {
+	if (homekit_mdns_started) {
+		homekit_mdns_started = false;
+		MDNS.close();
+	}
+	if (running_server) {
+		server_free(running_server);
+	}
+}
+
 void arduino_homekit_loop() {
 	if (homekit_mdns_started) {
 		MDNS.update();

src/arduino_homekit_server.h

@@ -226,6 +226,7 @@ typedef struct _client_event {
 
 
 void arduino_homekit_setup(homekit_server_config_t *config);
+void arduino_homekit_close();
 void arduino_homekit_loop();
 
 homekit_server_t * arduino_homekit_get_running_server();