[skeleton,pyramid] Move pyramid app definition in cubicweb.pyramid module The application definition is actually not specific to the final "cube" being bootstrapped from skeleton. This patch thus move the pyramid application function into cubicweb.pyramid module and let cubicweb register the "paste.app_factory" entry point (instead of the bootstrapped cube). Useless call to `config.scan` is dropped along the way.

[pyramid] Add a copyright and docstring to all modules We add copyright statements for both UNLISH (original author) and LOGILAB.

[cwconfig] Strip "cubicweb_" prefix from cube name in available_cubes() Closes #17054738.