[facet js] fix reordering of facet check boxes. Closes #2732947 Before this patch, when one select an element, it's moved to the top of the select content. Fine. But when it's later deselected, it stays there instead of moving back to its original location. This patch fixes that by introducing a facetCheckBoxReorder function which properly reorder the whole facet, instead of buggy attempt to locally reorder.

Additional services
===================

In this chapter, we introduce services crossing the *web -
repository - administration* organisation of the first parts of the
CubicWeb book. Those services can be either proper services (like the
undo functionality) or mere *topical cross-sections* across CubicWeb.

.. toctree::
   :maxdepth: 2

   undo