refactored redis implementation

roles/docker-funkwhale/templates/docker-compose.yml.j2

@@ -10,12 +10,9 @@ services:
     volumes:
       - database:/var/lib/postgresql/data
 
-  redis:
-    restart: always
+{% include 'templates/docker-redis-service.yml.j2' %}
+
     env_file: .env
-    image: redis:7-alpine
-    volumes:
-      - redis:/data
 
   celeryworker:
     restart: always