add force option to confd file resource

[martinpfeifer]

We've encountered an issue with Puppet trying to purge the confdir. We organise our Apache config in a conf.d style manner. When Puppet is instructed to purge a directory which contains directories it will complain that you must set the force parameter to really delete directories (see https://docs.puppet.com/puppet/3.8/reference/type.html#file-attribute-purge).
We think that purging the confdir should also include directories that may be present.
What do you think about this?

Notice: /Stage[main]/Apache/File[/etc/httpd/conf.d/test.d]: Not removing directory; use 'force' to override