Work-in-progress commit of the LDAP docs.

Think I'm going to discard most of these changes, but want to keep them around just in case I decide to revisit this approach.
Added some DNS troubleshooting notes.
Described how to use Kerberos auth (where needed).

Not actually using this anywhere, as it turns out. Thought I would be, though, and it's likely to be useful in the future.
Added configuration on how to install Tomcat.

Also added some additional LDAP configuration that's used by Tomcat.