Adding basic SSL support for default vhost template

* Adds new SSL cert params that can be passed to apache::vhost that
will be added to the default vhost template if ssl is set to true.

* Also fixes a bug in redhat-based systems where the
/etc/httpd/conf.d/ssl.conf file provided by the mod_ssl rpm would get
removed without duplicating its functionality elsewhere (i.e., Listen
443)

* Updated with a couple of fixes found since the original pull request (https://github.com/puppetlabs/puppetlabs-apache/pull/104)