add little example for configuration generation using a Python script

etc/python/example.py

@@ -0,0 +1,92 @@
+#!/bin/env python3
+''' Example Python config
+
+ This example demonstrates how you can use Python to generate complex
+ configuration files.
+
+ To use this configuration, run the following commands:
+
+    villas node <(python3 etc/python/example.py)
+
+ @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
+ @copyright 2014-2021, Institute for Automation of Complex Power Systems, EONERC
+ @license GNU General Public License (version 3)
+
+ VILLASnode
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+'''
+
+import json
+import sys
+
+N = 10
+
+nodes = {
+    'raspberry': {
+        'type': 'socket',
+        'layer': 'udp',
+        'format': 'protobuf',
+
+        'in': {
+            'address': '*:12000',
+        },
+        'out': {
+            'address': '1.2.3.4:12000'
+        }
+    }
+}
+
+for i in range(N):
+    name = f'agent{i}'
+    port = 12000 + i
+
+    nodes[name] = {
+        'type': 'socket',
+        'layer': 'udp',
+        'format': 'protobuf',
+
+        'in': {
+            'address': '*:12000',
+            'signals': [
+                {
+                    'name': 'in',
+                    'type': 'float'
+                }
+            ]
+        },
+        'out': {
+            'address': f'5.6.7.8:{port}'
+        }
+    }
+
+paths = [
+    {
+        'in': [f'agent{i}' for i in range(N)],
+        'out': 'raspberry',
+        'mode': 'any',
+        'hooks': [
+            {
+                'type': 'print'
+            }
+        ]
+    },
+]
+
+config = {
+    'nodes': nodes,
+    'paths': paths
+}
+
+json.dump(config, sys.stdout, indent=2)