s4:SAMLDB LDB module - Rework to allow checks for wrong "defaultObjectCategory" attri...

s4:SAMLDB LDB module - Rework to allow checks for wrong "defaultObjectCategory" attributes

This allows a stricter check for "defaultObjectCategory" attributes which is
performed when the "relax" control isn't specified.
Additional note: As the added comment points out this isn't complete.
And I personally think that moving this at some point to the "objectclass"
module is a better idea to make this fully work (since there we have direct
access to the schema). If someone has a good idea how to do this please inform
me.

Anyway, the SAMLDB module does require some restructure since at the moment it's
very overloaded and therefore a bit a mess. In the meantime I started to work
on a new approach to realise it in a better way.