[CDF-431] Centralize MessageBundlesHelper calls: move class to cpf-core

	- in Windows, CDF messages.properties url paths were incorrect, because FilenameUtils.normalize() ends up changing the path separator back to back-slash
	- so, switched order from FilenameUtils.normalize( FilenameUtils.separatorsToUnix() ) to FilenameUtils.separatorsToUnix( FilenameUtils.normalize() )