Add container for ELK stack

docker-compose/elk.yml

+#
+# Docker compose file that launches an ELK stack.
+# See https://elk-docker.readthedocs.io/
+#
+# Defines:
+#   - elk: ELK stack
+#
+version: '2'
+
+services:
+  elk:
+    image: sebp/elk
+    container_name: ${CONTAINER_NAME_PREFIX}elk
+    network_mode: ${NETWORK_MODE}
+    ports:
+      - "5601:5601"
+      - "9200:9200"
+      - "5044:5044"