fix(manifest): exclude file and add tox

MANIFEST.in

 include setup.py
 include README.rst
 include *.ini
+include *.py
 include dev-requirements.txt
 recursive-include cubicweb_addressbook *.py
 recursive-include cubicweb_addressbook/i18n *.pot *.po
 recursive-include cubicweb_addressbook/schema *.sql
 include test/data/bootstrap_cubes
 exclude .gitlab-ci.yml
+exclude cubicweb-addressbook.spec
+prune debian

tox.ini

@@ -24,6 +24,14 @@ commands = flake8
 max-line-length = 120
 exclude = cubicweb_addressbook/migration/*,.tox/*,
 
+[testenv:check-manifest]
+skip_install = true
+skipsdist = true
+deps =
+  check-manifest
+commands =
+  {envpython} -m check_manifest
+
 [testenv:pypi-publish]
 basepython = python3
 skip_install = true