Move the method used to create a config widget for a
RunConfigurationAspect from the RunControlFactory into the aspect
itself. This allows for aspects that are not bound to any factory,
which is what I eventually want to use to hold the environment for
run configurations.

Change-Id: Icceb5f44ca9eb63a87b9c7bb6468ff30dab943c2
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>