SLING-3651 : Applying patch from Konrad Windszus, thanks a lot! I've adjusted the patch slightly to not show the action when a project is already a content or a bundle project. IMO this is reasonably understandable (that a project can either be a content or a bundle project, not both. And we dont support automatic conversion from one to the other atm, that has to be done manually via facet fiddlings). i've also provided some more details as to which projects are listed in the 'convert to bundle project' wizard.

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1603446 13f79535-47bb-0310-9956-ffa450edef68