Issue/2926 reg app login

coscine/issues#2926

DON'T MERGE UNTIL coscine/issues#2932 IS DONE

.devcontainer/compose.yml

@@ -12,7 +12,7 @@ services:
     command: /bin/sh -c "while sleep 2s; do :; done"
     labels:
       - "traefik.enable=true"
-      - "traefik.http.routers.web-ui.rule=HostRegexp(`^web-ui-.*$`)"
+      - "traefik.http.routers.web-ui.rule=HostRegexp(`^coscine-.*$`)"
       - "traefik.http.routers.web-ui.entrypoints=web"
     volumes:
       - ..:/workspace/app:cached