Added Foreman Procfile for easier development running.

Foreman is the tool of choice for manageing processes on Heroku, so it is
“battle tested”. It starts all or one processes as defined in the Procfile,
e.g. `foreman start` starts all. `foreman start web` starts webserver etc.

This needed some other minor changes that were preventing a few things:

- fixed trailing whitespaces in puppet files
- allowed using the puppet gem provider