Add the scripts into the package

Currently, the scripts are only in the git repository but not installed by pip (not included in the package which is under /src. The scripts should be delivered as console scripts in the sense of this article.

With this move, the features that run_constraints.py and show_model.py provide, such as metamodel and model visualization (i.e. run only parser phase) and apply static constraints should go to the run_model.py script as options.