Clean-up of apt information in docker layers

Change-Id: I25949f4e61d327f61dfee8b7a9c3115738c445ac
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>
diff --git a/docker/LCM/Dockerfile b/docker/LCM/Dockerfile
index f7bcf09..7a5e376 100644
--- a/docker/LCM/Dockerfile
+++ b/docker/LCM/Dockerfile
@@ -68,7 +68,8 @@
 RUN DEBIAN_FRONTEND=noninteractive apt-get --yes update && \
     DEBIAN_FRONTEND=noninteractive apt-get --yes install \
     python3-minimal=3.6.* \
-    ca-certificates
+    ca-certificates \
+    && rm -rf /var/lib/apt/lists/*
 
 COPY --from=INSTALL /usr/lib/python3/dist-packages /usr/lib/python3/dist-packages
 COPY --from=INSTALL /usr/local/lib/python3.6/dist-packages  /usr/local/lib/python3.6/dist-packages
diff --git a/docker/MON/Dockerfile b/docker/MON/Dockerfile
index 7daa774..719d633 100644
--- a/docker/MON/Dockerfile
+++ b/docker/MON/Dockerfile
@@ -55,7 +55,8 @@
 RUN DEBIAN_FRONTEND=noninteractive apt-get --yes update && \
     DEBIAN_FRONTEND=noninteractive apt-get --yes install \
     python3-minimal=3.8.* \
-    ca-certificates
+    ca-certificates \
+    && rm -rf /var/lib/apt/lists/*
 
 COPY --from=INSTALL /usr/lib/python3/dist-packages /usr/lib/python3/dist-packages
 COPY --from=INSTALL /usr/local/lib/python3.8/dist-packages  /usr/local/lib/python3.8/dist-packages
diff --git a/docker/NBI/Dockerfile b/docker/NBI/Dockerfile
index 3b50256..4ac2a49 100644
--- a/docker/NBI/Dockerfile
+++ b/docker/NBI/Dockerfile
@@ -48,7 +48,8 @@
 FROM ubuntu:18.04 as FINAL
 
 RUN DEBIAN_FRONTEND=noninteractive apt-get --yes update && \
-    DEBIAN_FRONTEND=noninteractive apt-get --yes install python3-minimal=3.6.*
+    DEBIAN_FRONTEND=noninteractive apt-get --yes install python3-minimal=3.6.* \
+    && rm -rf /var/lib/apt/lists/*
 
 COPY --from=INSTALL /usr/lib/python3/dist-packages /usr/lib/python3/dist-packages
 COPY --from=INSTALL /usr/local/lib/python3.6/dist-packages  /usr/local/lib/python3.6/dist-packages
diff --git a/docker/NG-UI/Dockerfile b/docker/NG-UI/Dockerfile
index b7ca8f7..163441f 100644
--- a/docker/NG-UI/Dockerfile
+++ b/docker/NG-UI/Dockerfile
@@ -27,7 +27,8 @@
 RUN curl -s https://deb.nodesource.com/gpgkey/nodesource.gpg.key | apt-key add - && \
     echo "deb https://deb.nodesource.com/node_10.x xenial main" | tee -a /etc/apt/sources.list.d/nodesource.list && \
     apt-get update && \
-    apt-get install -y nodejs=10.24.*
+    apt-get install -y nodejs=10.24.* \
+    && rm -rf /var/lib/apt/lists/*
 
 ARG OSM_NGUI_URL
 
diff --git a/docker/PLA/Dockerfile b/docker/PLA/Dockerfile
index 712a095..8d4350b 100644
--- a/docker/PLA/Dockerfile
+++ b/docker/PLA/Dockerfile
@@ -46,7 +46,8 @@
 LABEL authors="Lars-Göran Magnusson"
 
 RUN DEBIAN_FRONTEND=noninteractive apt-get --yes update && \
-    DEBIAN_FRONTEND=noninteractive apt-get --yes install python3-minimal=3.6.*
+    DEBIAN_FRONTEND=noninteractive apt-get --yes install python3-minimal=3.6.* \
+    && rm -rf /var/lib/apt/lists/*
 
 COPY --from=INSTALL /usr/lib/python3/dist-packages /usr/lib/python3/dist-packages
 COPY --from=INSTALL /usr/local/lib/python3.6/dist-packages  /usr/local/lib/python3.6/dist-packages
diff --git a/docker/POL/Dockerfile b/docker/POL/Dockerfile
index f78283a..3e708b7 100644
--- a/docker/POL/Dockerfile
+++ b/docker/POL/Dockerfile
@@ -48,7 +48,8 @@
 FROM ubuntu:20.04 as FINAL
 
 RUN DEBIAN_FRONTEND=noninteractive apt-get --yes update && \
-    DEBIAN_FRONTEND=noninteractive apt-get --yes install python3-minimal=3.8.*
+    DEBIAN_FRONTEND=noninteractive apt-get --yes install python3-minimal=3.8.* \
+    && rm -rf /var/lib/apt/lists/*
 
 COPY --from=INSTALL /usr/lib/python3/dist-packages /usr/lib/python3/dist-packages
 COPY --from=INSTALL /usr/local/lib/python3.8/dist-packages  /usr/local/lib/python3.8/dist-packages
diff --git a/docker/RO/Dockerfile b/docker/RO/Dockerfile
index ba7d54d..04f7c4c 100644
--- a/docker/RO/Dockerfile
+++ b/docker/RO/Dockerfile
@@ -81,7 +81,8 @@
 FROM ubuntu:18.04
 
 RUN DEBIAN_FRONTEND=noninteractive apt-get --yes update && \
-    DEBIAN_FRONTEND=noninteractive apt-get --yes install python3-minimal=3.6.*
+    DEBIAN_FRONTEND=noninteractive apt-get --yes install python3-minimal=3.6.* \
+    && rm -rf /var/lib/apt/lists/*
 
 COPY --from=INSTALL /usr/lib/python3/dist-packages /usr/lib/python3/dist-packages
 COPY --from=INSTALL /usr/local/lib/python3.6/dist-packages  /usr/local/lib/python3.6/dist-packages