不满足重定向获取网上资源的条件，进行本地获取

直接重定向到网址获取资源

1. urls

urlpatterns = [
    path("", RedirectView(settings.FAVICON),
    ]

2. settings

FAVICON = _get_config("FAVICON", "https://.../")

无法从网站获取资源时，本地提供

1. urls

urlpatterns = [
    path("", core_views.favicon_view),
    ]

2. settings

FAVICON = _get_config("FAVICON", "https://.../")

3. views

def favicon_view(request):
    if settings.FAVICON:
        return redirect(settings.FAVICON)
    return FileResponse(open("core/static/", "rb"))