(Readdition of www/trac-ldap which was removed on 349600)

LDAP extensions to grant group permissions

This extension enables the use of existing LDAP groups to grant
permissions rather than defining permissions for every single user on
the system. Also permits storage of permissions (both users and
groups permissions) in the LDAP directory itself rather than in the
database backend.

WWW: https://trac-hacks.org/wiki/LdapPlugin

Reviewd by: koobs
Differential Revision: https://reviews.freebsd.org/D4796