Adding a command line script and pipeline configuration parser

[jucordero]

Register a command line script which allows to run agrifoodpy directly outside a python environment, as long as a configuration file exists.
This also requires adding a configuration parser to define pipelines using either a .yaml or .ini file

The goal is to be able to run agrifoodpy like this:

agrifoodpy config.yml -o output.json --from-node 1 --skip-nodes 2 8

This should be relatively straightforward, as registering console scripts is easy with setup.py and a config parser for the type of pipeline descriptions we have is easy to achieve with yaml files.