Add a new role that will provision a wiki that uses LDAPAuth and an ldap server to interact with.
The patch *almost* works. It turns out that there is a conflict with the bootstrapping of role::centralauth which was masked in my local testing due to CA being enabled on my local ldapauth wiki initially. The problem is that role::centralauth runs Mediawiki::Maintenance['Pass 0 of CentralAuth'] for all wikis (using the alldbs generated dblist). It really should use a dblist that only includes wikis where CA is installed.