Add more debug for LDAP connections and user authentication

There are multiple steps involved to authentication user via ldap. 

1. LDAP connections details - Logs do indicate that there are connection issues, and user can figure out based on connection details of the error message. 
2. Attaching of user dn for find user in ldap server. This is tricky part. Current setting is a regex and there might be issues with regex setup. If there are errors with regex debug.log only prints - Bind for dn "<ud>bjones01</ud>": {error,invalidDNSyntax}
   It would be nice to print the exact user DN added for bind, and then a syntax error, to know what is getting passed to ldap server in terms of full bind details or it is a problem with regexp.