Docker-compose: do not access ports <443 (#3261)

* Do not try accessing ports <1024

* adapt nginx reverse proxy for element web

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Co-authored-by: fkwp <github-fkwp@w4ve.de>

backend/dev_nginx.conf

@@ -145,11 +145,11 @@ server {
       proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
       proxy_set_header X-Forwarded-Proto $scheme;
 
-      proxy_pass http://element-web:81;
+      proxy_pass http://element-web:8081;
       proxy_ssl_verify              off;
 
     }
     
     error_page   500 502 503 504  /50x.html;
 
-}
+}