Univention Corporate Server 4.4 erratum 102 (bugfix)

This update addresses the following issues:
* Explicit initialization of the default values of UDM properties has been
  removed from the code of all UDM modules.
* The users/user UDM module now uses the ldap filter
  "univentionObjectType=users/user" when searching for objects to increase
  performance.
* When opening container objects, a lookup is performed to check whether
  this container is the default container for certain UDM objects. This
  lookup is now cached which makes opening many objects at once considerably
  faster.
* After renaming an object the internal DN (self.dn) is updated correctly.
  The old DN can now be obtained via self.old_dn. This fixes the concurrent
  renaming and update of group membership for e.g. computer objects.
* Several german translations have been updated.