examples/ip_pipeline: add config diagram generator

This commit adds Python script for generating diagram of the application
configuration file. This script requires graphviz package to be installed
on the machine. The input config file is translated to an output file in
DOT syntax, which is then used to create the image file using graphviz.

To run the script, following command is used;

./diagram-generator.py -f <input configuration file>

Some optional arguments are as follows:
  -h, --help            show this help message and exit

Signed-off-by: Jasvinder Singh <jasvinder.singh@intel.com>
Signed-off-by: Cristian Dumitrescu <cristian.dumitrescu@intel.com>
Acked-by: John McNamara <john.mcnamara@intel.com>