Deploy with tests to corresponding db cluster

This PR adds new deploy scripts. With these, it will be possible to

- deploy the project to any target from inside the working directory
- run the nosetests against the db cluster corresponding to the target.

This removes the need to be inside /var/www to do deploys. It replaces our chsdi3 deploy scripts from https://github.com/geoadmin/deploy

The script will abort directly when this occurs, and thus it's very visible in the UI that it happens. You can then simply relaunch the script with the same command.