NAMESPACE is intranet, not fresh

We are going to be compatible python 3 only

- update __pkginfo__.py and use cubicweb[pyramid] '>= 3.26.0, < 3.27'
- update README file
- update setup.py to read from README.rst not README

- install from Debian Buster as base image so that we can use Python 3.7
- install current source code for fresh cube
- install additional requirements from docker/requirements.txt

- add docker/entrypoint.sh to define available entrypoints for the instance
- add docker/pyramid.ini.j2 that will be used to create the instance
- add docker/uwsgi.ini that will be used to start the instance
- add .dockerignore file to build a smaller image

- fix DeprecationWarning: [3.22] Use 'from cubicweb import _'
- fix DeprecationWarning: [3.16] moved to cubicweb.web.views.uicfg
- fix DeprecationWarning: [3.15] cubicweb.selectors renamed into cubicweb.predicates

- use print as a function
- use range function instead of xrange function

- move files to cube folder
- add basic README
- update __pkginfo__.py to use cubicweb 3.24
- update MANIFEST.in, setup.py
- update how cubes are imported, use new style

This is weird as Training are defined and used by our internal crm cube, but
we've to define it here as well until we've a way to say "import trainings as if
they were workcases".

Closes #3181451

Use python-support to ship and clean up pyc files properly
Update debhelper compat and policy version
Add (no-op) build-arch target

pkginfo and debian/copyright disagreed on the license.  The relevant
authority has confirmed that the correct license is LGPL.

Closes #3120346