R1:0a0607d2f706

Support searching for users to find their LDAP entry

Summary:
- the current LDAP auth flow expects a DN to look like
cn=ossareh,ou=Users,dc=example,dc=com
- however many LDAP setups have their dn look something like
cn=Mike Ossareh,ou=Users,dc=example,dc=com

Test Plan:
Test if logins work with a LDAP setup which has cn=Full Name
instead of cn=username.

To test you should ensure you set the properties needed to
trigger the search before login as detailed in conf/default.conf.php

Reviewers…