[pkg] Add new autopkgtest for skeleton packaging
When running `cubicweb-ctl newcube`, the generated template provides
debian packaging. So let's add automated tests for that using
autopkgtest.
The new test will generated a new cube, build a source tarball,
build the package, try to install it, see if the Python 2 and 3
modules are available and even run autopkgtest against the newly
created packages.
Along the way it will also print information about the generated
package: buildinfo, package content, and lintian report.
Add some entities
-----------------
As manager, you can access to entity creation forms by using the `site management`_ page.
.. _`site management`: ../manage
As regular user, the index page or the action box may propose some links to create entities according to the context.