Chores: add missing profile for middleware docker compose cmd and fix ssrf-proxy doc link (#6372)

Co-authored-by: crazywoola <100913391+crazywoola@users.noreply.github.com>

api/README.md

    ```bash
    cd ../docker
    cp middleware.env.example middleware.env
-   docker compose -f docker-compose.middleware.yaml -p dify up -d
+   # change the profile to other vector database if you are not using weaviate
+   docker compose -f docker-compose.middleware.yaml --profile weaviate -p dify up -d
    cd ../api
    ```
 

docker/docker-compose.middleware.yaml

 
   # ssrf_proxy server
   # for more information, please refer to
-  # https://docs.dify.ai/getting-started/install-self-hosted/install-faq#id-16.-why-is-ssrf_proxy-needed
+  # https://docs.dify.ai/learn-more/faq/self-host-faq#id-18.-why-is-ssrf_proxy-needed
   ssrf_proxy:
     image: ubuntu/squid:latest
     restart: always