Migrate Dockerfile.be to unprivileged user

Issue-ID: PORTAL-849
Change-Id: I58fe742980a24039114033a82fe785a1093391bf
Signed-off-by: Pawel Wieczorek <p.wieczorek2@samsung.com>
(cherry picked from commit 047385e55632a1dd6398e414aa82397f380e449f)
diff --git a/deliveries/Dockerfile.be b/deliveries/Dockerfile.be
index afc3981..21bb1a2 100644
--- a/deliveries/Dockerfile.be
+++ b/deliveries/Dockerfile.be
@@ -39,7 +39,9 @@
 
 VOLUME ${TOMCATHOME}/logs
 
+# Switch to unprivileged user
 RUN addgroup -g 1000 -S portal && adduser -u 1000 -S portal -G portal && chown -R portal:portal . && chmod -R 777 /etc/ssl/certs/java /var/
+USER portal
 
 # Switch back to root
 WORKDIR /