Python: Add a Dockerfile for a python environment

So I can test issue #304

docker/pyside2/Dockerfile

@@ -0,0 +1,36 @@
+#
+# This file is part of KDDockWidgets.
+#
+# SPDX-FileCopyrightText: 2019-2022 Klarälvdalens Datakonsult AB, a KDAB Group company <info@kdab.com>
+# Author: Sérgio Martins <sergio.martins@kdab.com>
+#
+# SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only
+#
+# Contact KDAB at <info@kdab.com> for commercial licensing options.
+
+# The purpose of this Dockerfile is just for quickly getting a running python build for testing.
+# Instructions:
+# $ docker build -t kddw-pyside2 .
+# $ docker run -it -v ~/Qt/5.15.2/gcc_64/:/Qt/ kddw-pyside2
+  # git checkout 1.6
+  # cmake --preset=python -G Ninja .
+  # cd build-python/ && ninja
+
+FROM ubuntu:22.04
+MAINTAINER Sergio Martins (sergio.martins@kdab.com)
+
+ENV TZ=Europe/Berlin
+ENV LC_CTYPE=C.UTF-8
+ENV DISPLAY=:0
+ENV PATH=$PATH:/Qt/bin/
+ENV LD_LIBRARY_PATH=/Qt/lib/
+
+RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
+
+RUN apt update
+RUN apt install build-essential software-properties-common git ninja-build libssl-dev mesa-common-dev libglu1-mesa-dev libglib2.0-dev libfontconfig libxkbcommon-x11-0 libdbus-1-3 cmake pip libxslt1-dev llvm-dev clang -y
+RUN pip3 install --index-url=http://download.qt.io/official_releases/QtForPython/ --trusted-host download.qt.io shiboken2 pyside2 shiboken2_generator
+
+WORKDIR /
+RUN git clone https://github.com/KDAB/KDDockWidgets.git
+WORKDIR /KDDockWidgets/