add a name() function to CreateClassCommand that expands to the default namespace given the class (BC break constructor but not fromContainer())
add createClass, ask, confirm and getInstallTemplate to installer interface and implement in PartsInstaller
add a InteractionHelper to partsInstaller to allow asking questions
refactor Container to provide the InteractionHelper
fix alle tests to tprovide the InteractionHelper to partsInstallerClass
add CreateClassCommand for implementation of createClass
add a CMSContainerPart which installs an abstract contrainer for Psc-CMS