Use requirements.txt file to manage pip requirements

docker-compose/itango/Dockerfile

@@ -6,6 +6,7 @@ RUN sudo apt-get -y update && \
     sudo apt-get -y install apt-file apt-transport-https apt-utils aptitude && \
     sudo aptitude -y install htop iftop iproute2 mc most net-tools tcpdump telnet tmux traceroute vim xterm && \
     sudo aptitude clean && \
-    sudo aptitude autoclean && \
-    sudo pip3 install "opcua >= 0.98.9" asyncua astropy
+    sudo aptitude autoclean
 
+COPY lofar-requirements.txt /lofar-requirements.txt
+RUN sudo pip3 install -r /lofar-requirements.txt

docker-compose/itango/lofar-requirements.txt

+opcua >= 0.98.9
+astropy