Make job submission system configurable

[elfring]

I guess that parallel execution of build jobs is also supported by your software. These jobs will be run by a local build environment so far. It can happen that the computing resources can become too limited for a challenging data processing application there.

I suggest to extend corresponding resources with capabilities from distributed systems. Some programming interfaces are available for such a purpose. How do you think about to make it possible to choose from various job submission systems by configuration variables?