Add a target_file_ensure parameter to each object type and pass it through to the underlying file resource. The parameter default values are 'file', but having the ensure => parameter of the underlying file type be settable by the user lets people do things like setting target_file_ensure to absent so that they can remove object files via Puppet (instead of manually).

refs#7716 : https://dev.icinga.org/issues/7716
Merge branch 'feature/7716/ensureable_object_params'

refs#7716: https://dev.icinga.org/issues/7716