Run Dashboard container as non-root user

Add 'nginx' user to Dashboard container to avoid running container as
root user.

Running containers with 'root' user can lead to a container escape
situation. It is a best practice to run containers as non-root users.

dashboard/Dockerfile

@@ -12,6 +12,14 @@ CMD npm run dev
 FROM nginx:alpine
 RUN apk add --no-cache bash
 
+ARG USER_ID=1000
+ARG GROUP_ID=1000
+RUN addgroup -g ${GROUP_ID} -S nginx
+RUN adduser -u ${USER_ID} -S -D nginx nginx
+USER nginx
+
+RUN chown -R nginx:nginx /var/cache/nginx /var/run /usr/share/nginx/html
+
 ARG VERSION_PATH
 ARG VERSION_LONG
 ARG VERSION_SHORT