[server/test] Drop dependency on folder cube
Just copy schema bits when needed and drop a view (not possible anymore) in
unittest_repository.
Closes #5168939.
Schema of the data
------------------
First take a look at the data schema_ then try to remember that you are browsing
through a heap of data by applying stylesheets to the results of queries. This
site is not a content management system with items placed in folders. It is an
interface to a database which applies a view to retreived data.
.. _schema: ../schema