[FIX] packaging: add qrcode package to docker file

After the Odoo package is built, the package.py script uses a Docker
image to test the package. After that python3-qrcode was added as a
dependency for the package in 2ff49c5f , it revealed some issues.

A missing cli parameter and a forgotten '&&' in the Dockerfile prevented
the installation of the depending packages.

Also, the script shebang was wrong by launching python2.

Finally, the fact that python3-xlwt is missing in Debian stretch was
highlighted. With this commit, the python3-xlwt is explicitly removed
from the dependencies and the documentation is updated accordingly.

closes odoo/odoo#28807

debian/py3dist-overrides

+xlwt

doc/setup/install.rst

@@ -169,21 +169,15 @@ Or ``dpkg``:
 This will install Odoo as a service, create the necessary PostgreSQL_ user
 and automatically start the server.
 
-.. warning:: The 3 following python packages are only suggested by the Debian package.
-             Those packages are not available in Ubuntu Xenial (16.04).
+.. warning:: The python3-xlwt Debian package does not exists in Debian Stretch nor Ubuntu 18.04.
+             This python module is needed to export into xls format.
 
-* python3-vobject: Used in calendars to produce ical files.
-* python3-pyldap: Used to authenticat users with LDAP.
-* python3-qrcode: Used by the hardware driver for ESC/POS
-
-If you need one or all of the packages mentioned in the above warning, you can install them manually.
+If you need the feature, you can install it manually.
 One way to do it, is simply using pip3 like this:
 
 .. code-block:: console
 
-    $ sudo pip3 install vobject qrcode
-    $ sudo apt install libldap2-dev libsasl2-dev
-    $ sudo pip3 install pyldap
+    $ sudo pip3 install xlwt
 
 .. warning:: Debian 9 and Ubuntu do not provide a package for the python module
              num2words.

setup/package.dfdebian

@@ -15,7 +15,7 @@ ENV LC_ALL C.UTF-8
 
 RUN apt-get update -qq &&  \
     apt-get upgrade -qq -y && \
-    apt-get install \
+    apt-get install -qq -y\
         adduser \
         postgresql \
         postgresql-client \
@@ -40,6 +40,7 @@ RUN apt-get update -qq &&  \
         python3-pydot \
         python3-pyparsing \
         python3-pypdf2 \
+        python3-qrcode \
         python3-reportlab \
         python3-requests \
         python3-serial \
@@ -49,7 +50,7 @@ RUN apt-get update -qq &&  \
         python3-vatnumber \
         python3-vobject \
         python3-werkzeug \
-        python3-xlsxwriter \
+        python3-xlsxwriter && \
     rm -rf /var/lib/apt/lists/*
 
 RUN echo "PS1=\"[\u@nightly-tests] # \"" > ~/.bashrc

setup/package.py

-#!/usr/bin/env python2
+#!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 from __future__ import print_function