Remove "clean" goal trigger from the "prepare-package" phase of all/*

To resolve ISPN-4939 a "clean" goal was attached to the "prepare-package" phase.

This fix is not appropriate in combination with ISPN-4942 (uberjars in OSGi) as needed resources are created before this phase ("initialize" is not appropriate as a clean will be triggered when the distribution module prepares the javadoc and before the uberjars are added to the distribution package).