r17860: Let's commit the work down up to now on the new schema module.

r17860: Let's commit the work down up to now on the new schema module.
At the moment it is able to validate an object has no conflicting
objectlasses that it meets the criteria to be inserted as child of
the parent and also sorts and create the objectclass hierarchy so
that the objectclass .c module can be obsoleted.

Not activated by default as we have to completely rework the
current provisioning method. (In my tests I could not activate
it before all other ldif except for the one that create users
were loaded, make test seem to be happy anyway if it is activated
after provisioning).

Next steps will be attribute and attribute syntax checking on add operation.
And then the modify operation will follow.

Simo.
(This used to be commit 0c444ba1adfb9ce5cfa736bf0620aa3bec66050d)