Complete machinery command in config_file_diff code path
Use scope_extracted? instead of file_store
Use $0 instead of machinery in list_task
Add packages and changed-managed files to description factory
Add new error class MissingExtractedFiles

We have two commands which complain if non extracted scopes exist so
we combine them to one error class with a proper error messages which
also shows the command how to extract the missing scopes.
Merge pull request #282 from SUSE/complete_command_suggestions3

Complete command suggestions3