remove dep on the epel class (stahnma/puppet-module-epel)

This module does not have any provision for using local / private EPEL mirrors
add pureftpd::config params for almost all pure-ftpd.conf variables
properly fail on $::osfamily = debian
convert pureftpd::config from a defined type into a class
restructure module so all classes for the inheritance hierarchy pureftpd -> pureftpd::params -> pureftpd::<foo>
add ldap/mysql/pgsql parameters to pureftpd::config

As a replacement for `$default_auth` used the templates
lowercast camel case template dir name
convert define pureftpd::config_ldap into a class