WIP DO NOT MERGE: add support for keystone::ldap

With packstack, I can pass in "global parameters" via hiera.  I'm not sure what to do here.  It seems like adding 40-odd class parameters to quickstack::keystone::common (and quickstack::pacemaker::keystone) isn't the right thing to do.
all these probably need to be params on this class, and you _may_ want to prepend them with 'ldap', like:
```
$ldap_url
```

etc