backend: allow '/' in image names

backend/backend/v1_images.py

@@ -10,7 +10,7 @@ from .cyberjudo import CyberJudo
 def get_images_router(cyberjudo: CyberJudo, images_dir: str, cjc: CyberJudoCrypto):
     router = APIRouter()
 
-    @router.get('/named-images/{name}', response_class=FileResponse,
+    @router.get('/named-images/{name:path}', response_class=FileResponse,
                 description='this directly returns an image (mime type depending on the file), if known')
     def get_image_by_name(name: str):
         if not cyberjudo.image_is_known(name):