feat(docker): add SITAR API environment variables and configure backend uploads volume

docker-compose.yml

@@ -188,6 +188,7 @@ services:
     volumes:
       - ./backend:/app
       - backend_cache:/app/__pycache__
+      - backend_uploads:/app/uploads
       - ./scripts/backend-entrypoint.sh:/entrypoint.sh:ro
     networks:
       - backend-net
@@ -298,6 +299,8 @@ volumes:
     driver: local
   backend_cache:
     driver: local
+  backend_uploads:
+    driver: local
 
 networks:
   backend-net: