Add 'gui' docker files, which include running X11 via a VNC server

docker/gui/fedora-30/Dockerfile

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+FROM wxpython/build:fedora-30
+
+RUN sudo dnf -y install tigervnc-server xterm
+RUN mkdir ~/.vnc
+
+# RUN sudo dnf -y install fluxbox
+# RUN echo "fluxbox &"> ~/.vnc/xstartup
+
+# RUN sudo dnf -y install @xfce-desktop-environment
+# RUN echo "startxfce4 &"> ~/.vnc/xstartup
+
+# RUN sudo dnf -y install --allowerasing @mate-desktop-environment
+# RUN echo "mate-session &"> ~/.vnc/xstartup
+
+RUN sudo dnf -y install @lxde-desktop-environment
+RUN echo "startlxde &"> ~/.vnc/xstartup
+
+
+RUN chmod u+x ~/.vnc/xstartup
+RUN echo "password" | vncpasswd -f >> ~/.vnc/passwd
+RUN chmod 600 ~/.vnc/passwd
+
+CMD ["start-vncserver.sh"]

docker/gui/ubuntu-18.04/Dockerfile

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+FROM wxpython/build:ubuntu-18.04
+
+USER root:root
+RUN apt-get install -y \
+        libx11-6 libxcb1 libxau6 xterm \
+        tightvncserver \
+        xvfb dbus-x11 x11-utils \
+        xfonts-base xfonts-75dpi xfonts-100dpi \
+# Choose one of these:
+#        lxde
+        lubuntu-desktop
+#        ubuntu-mate-desktop
+
+USER ${USER}:${USER}
+RUN touch ~/.Xauthority; \
+        mkdir ~/.vnc; \
+        echo "password" | vncpasswd -f >> ~/.vnc/passwd; \
+        chmod 600 ~/.vnc/passwd; \
+# And a coresponding one of these:
+#        echo "exec /usr/bin/startlxde" > ~/.vnc/xstartup;
+        echo "exec lxsession -e LXDE -s Lubuntu" > ~/.vnc/xstartup;
+#        echo "exec mate-session" > ~/.vnc/xstartup;
+
+RUN chmod +x ~/.vnc/xstartup;
+
+CMD ["start-vncserver.sh"]

docker/scripts/start-vncserver.sh

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+#!/bin/bash
+echo "starting VNC server ..."
+vncserver :1 -geometry 1600x1050 -depth 24 && tail -F ~/.vnc/*.log