[rqlrewrite] Enhance detection of need for Exists node
We actually want one only if this is not a (`And` / `Or`) binary tree of `Not` or
`Exists` nodes, so write a recursive function to tell so.
Related to #17074119
.. _TutosPhotoWebSite:
Building a photo gallery with |cubicweb|
========================================
Desired features
----------------
* basically a photo gallery
* photo stored on the file system and displayed dynamically through a web interface
* navigation through folder (album), tags, geographical zone, people on the
picture... using facets
* advanced security (not everyone can see everything). More on this later.
.. toctree::
:maxdepth: 2
part01_create-cube
part02_security
part03_bfss
part04_ui-base
part05_ui-advanced