L2SS-475: test docker secret

docker-compose/archiver-timescale.yml

 version: '2'
 
+secrets:
+  pg_password:
+    external: true
+
 services:
   archiver-timescale:
     image: timescaledb
@@ -10,10 +14,13 @@ services:
       - control
     ports:
       - "5432:5432/tcp"
+    secrets:
+      - source: pg_password
+        target: POSTGRES_PASSWORD
     depends_on:
       - databaseds
     environment:
-      - POSTGRES_PASSWORD=password
+      - POSTGRES_PASSWORD_FILE= '/run/secrets/db_password'
       - TANGO_HOST=${TANGO_HOST}
     logging:
       driver: syslog