enable adding custom config widgets from a run control factory

To achieve this there are two methods in IRunControlFactory you
need to implement:

1) createRunConfigurationAspect returns a IRunConfigurationAspect
which stores the settings specific to your plugin.
2) createConfigurationWidget returns a RunConfigWidget that will
be shown in the project settings

Merge-request: 258
Reviewed-by: hjk <qtc-committer@nokia.com>