fix: correct URL format in docker-compose files and improve viewport handling in index.php

docker-compose.yml

@@ -1,9 +1,10 @@
-version: '3.3'
 services:
   http2pic:
     image: gitea.haschek.at/haschek-solutions/http2pic:2
     restart: unless-stopped
-
+    volumes:
+      - ./cache:/srv/cache
+      - ./logs:/srv/logs
     environment:
       - URL=http://localhost:8080
     ports: