Scripts to facilitate setup and execution of Docker Compose app

[henrikplate]

This PR aims at facilitating the setup and execution of Steady's Docker Compose application with the two bash scripts setup-steady.sh and start-steady.sh.

Moreover, the file .steady.properties in the user's home directory can be used to store user-specific configuration settings.

In this context, the filename pattern of configuration files has been changed from vulas-*.properties to steady-*.properties. Still, configuration files adhering to the old pattern are still considered - as long as they exist in the file system (opposed to being part of JAR or WAR files).

TODOs

• Tests
• Documentation

[serenaponta]

Just few minor comments:

• i would add a comment in "docker-compose-new.yml" to document its purpouse.
• on top of explaining how to start the backend, i would also add a one line on how to stop it (though it should be obvious i would still add it)