Simplified the config for ONOS simple GUI.

This should make it more user-friendly for new developers.
All config not used by this GUI has been removed from the config file.
Instructions have been added on how to create a local config file.

The GUI script can now be run from any working directory.

Change-Id: I5a4b75bf383816e1143540ebbc6f9a274dab4949
diff --git a/web/config.json.default b/web/config.json.default
new file mode 100644
index 0000000..88fc2e7
--- /dev/null
+++ b/web/config.json.default
@@ -0,0 +1,12 @@
+{
+    "gui-ip" : "0.0.0.0",
+    "gui-port" : 9000,
+    "onos-ip" : "localhost",
+    "onos-port" : 8080,
+    "controllers": [
+        "onos-vm1", 
+        "onos-vm2", 
+        "onos-vm3", 
+        "onos-vm4"
+    ]
+}