Add floof collaborator; traefik labels + service; rename .env.example->.env; opencloud.maukit.com entrypoints

- .env renamed (.env.example removed); domain -> opencloud.maukit.com / euro-office.opencloud.maukit.com
- docker-compose.yml: opencloud labels traefik (Host opencloud.maukit.com, websecure, letsencrypt); OC_URL updated
- traefik/service.yml: traefik v2.10.4 service matching floof/portainer style (docker.sock, ports 80/443/8080)
- Compare with floof/portainer traefik/docker-compose.yml: same label structure (enable=true, Host, entrypoints, tls.certresolver)
- floof added to repo (collaborator) per convention
- No deploy; reference only

traefik/service.yml

@@ -0,0 +1,17 @@
+  traefik:
+    image: traefik:v2.10.4
+    container_name: traefik
+    security_opt:
+      - no-new-privileges:true
+    ports:
+      - "80:80"
+      - "443:443"
+      - "8080:8080"
+    volumes:
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+      - ./traefik/traefik.yml:/etc/traefik/traefik.yml:ro
+    networks:
+      - opencloud-net
+    restart: unless-stopped
+    labels:
+      - "traefik.enable=true"