[skeleton] Update Debian packaging template Here are multiple updates to the Debian packaging template provided when running `cubicweb-ctl newcube`: * Switch to source format 3.0 (quilt). * Switch to debhelper 9. * Switch to dh-python. * Add Python 3 packages. * Name the binary packages `python-cubicweb-CUBENAME` and `python3-cubicweb-CUBENAME` instead of just `cubicweb-CUBENAME` (which is still the source package). * Populate Depends using dh_python{2,3} support for Python requirements. * Run test suite at build time using pytest. * Add autopkgtest to run test suite against the installed package. * Bump Standards-Version to 4.3.0.

### Requirements for tests in various cubicweb/**/test directories. ###

## shared by several test folders
cubicweb-card == 0.5.8
docutils
Twisted < 16.0.0
webtest

## cubicweb/test
Pygments
pycrypto
mock
#fyzz XXX pip install fails
cubicweb-file == 1.18.0
cubicweb-localperms == 0.3.2
cubicweb-tag == 1.8.3

## cubicweb/devtools/test
flake8

## cubicweb/hooks/test
psycopg2-binary

## cubicweb/pyramid/test
pyramid >= 1.5.0
waitress >= 0.8.9
wsgicors >= 0.3
pyramid_multiauth
repoze.lru

## cubicweb/sobject/test
cubicweb-comment == 1.12.2