Created first simple workflow example for the data_logger

To start the logger use:
python data_logger.py -c <config-file> [-m <host-address> -p <host-port>]
The config file path is needed, but does nothing at the moment. The programm writes
2 variables from the Barometer(Air Pressure and Altitude) into a pre defined CSV File
(logged_data.csv in the same folder as data_logger.py)

TODO:
- parse config.ini for configurations
- get HOST and PORT from config.ini OR command-line
- more exception and error handling!
- fix the thread_sleep magic number (still to unreliable!)