(PUP-3127) LDAP - introduce LDAP-Certificat Directory

Add ldapcrtdir settings to enable ssl based ldap connections on Solaris based Puppet-Master.
Without this implementation it is not possible to create ssl encrypted ldap connections on a Solaris system.
If the 'ldapcrtdir' parameter is not set or set to false (=> default), the connection is etablished as before.
If crtdir is nil, it would be more secure to try using `/var/ldap` on Solaris 10 if the directory exists. Something like, query Facter.value(:osfamily) == 'Solaris' and Facter.value(:operatingsystemmajrelease) < '11'. I'd also suggest adding a warning if ldapcrtdir is set and doesn't exist.