[server] extract "no pooler" CnxSet class to a _BaseCnxSet class
So we get rid of "if self._queue is None" in each method of _CnxSetPool
Also add helper get_cnxset(source, size) to instantiate the correct pooler class.
:mod:`cubicweb.pyramid`
=======================
.. automodule:: cubicweb.pyramid
.. autofunction:: wsgi_application_from_cwconfig
.. autofunction:: wsgi_application
.. toctree::
:maxdepth: 1
:glob:
pyramid/*