[pkg] Add python-logilab-constraint to debian dependencies
else we may run into problem when pkg_resources is used, as it will detect that
a dependancy in the python package isn't installed.
Fix it this way rather than using extras_require because we want the
package to be usable with a simple pip install.
Closes #9343431
TODO list for the rql package
=============================
* retirer les restrictions e_type = [A-Z][a-z_]*
r_type = [a-z_]*
* detecter les erreurs ASAP pour éviter stcheck
* tests unitaires pour sqlgen
* revoir tutoriel
* specification 1.0