Avoiding the initialization of unused modules

[knoepfel]

The framework SHOULD only initialize those modules specified to be run. Any additional configuration data for other modules not in the list to be run (e.g. something pulled in from including/importing various common config files) should be ignored.

[knoepfel]

This idea was originally expressed by DUNE as a framework requirement. It was removed because it is suggested an implementation solving an unstated problem. It is relevant, however, insofar as the quality of implementation is concerned.