add console component and example

examples/system/console/main/cmd_decl.h

@@ -0,0 +1,15 @@
+/* Console example — declarations of command registration functions.
+
+   This example code is in the Public Domain (or CC0 licensed, at your option.)
+
+   Unless required by applicable law or agreed to in writing, this
+   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+   CONDITIONS OF ANY KIND, either express or implied.
+*/
+#pragma once
+
+// Register system functions
+void register_system();
+
+// Register WiFi functions
+void register_wifi();