Move `load_file_from_url`

Why?
one of the internal calls of `load_file_from_url` import cv2, which locks the cv2 site-package, which extensions may (and in our case, is) breaking the installation of some libraries. The base project should be limiting its import of unnecessary libraries when possible during the installation phase.

modules/modelloader.py

@@ -4,7 +4,6 @@ import shutil
 import importlib
 from urllib.parse import urlparse
 
-from basicsr.utils.download_util import load_file_from_url
 from modules import shared
 from modules.upscaler import Upscaler, UpscalerLanczos, UpscalerNearest, UpscalerNone
 from modules.paths import script_path, models_path
@@ -59,6 +58,7 @@ def load_models(model_path: str, model_url: str = None, command_path: str = None
 
         if model_url is not None and len(output) == 0:
             if download_name is not None:
+                from basicsr.utils.download_util import load_file_from_url
                 dl = load_file_from_url(model_url, model_path, True, download_name)
                 output.append(dl)
             else: