Hierachy aware layout should recognize separate connected components

[soerendomroes]

Hierarchy-aware layout can help to make global edge routing decisions, however, it does currently not handle separate connected components. I would also like to be able to recognize local separate components (e.g. components with external ports, which are no longer external because we do hierarchy-aware layout).

This is a very bad drawing that is achieved by introducing constraint, which should not be possible since there are three components in CustomerFactory.

If one sensibly sets constraints one can still optimize the position of "5" by putting it right of "4". bad: good:

Moreover, in the following graph it is not necessary to force the "1"-"2" component to the same grid as the rest: bad: good: