time out model downloads that never respond

`download_from_url` had no timeout, so a proxy or server that accepted the connection and never answered hung the download forever, including runtime downloads during startup. Connect and read timeouts now fail it like any other download error. The read timeout applies per socket read, so large models still finish.

frigate/util/downloader.py

@@ -14,6 +14,10 @@ from frigate.util.file import FileLock
 
 logger = logging.getLogger(__name__)
 
+# (connect, read) seconds. The read timeout bounds each socket read rather than
+# the whole download, so large models still finish.
+DOWNLOAD_TIMEOUT = (15, 60)
+
 # target path -> first line of the last download error for it; every existing
 # download function swallows its exceptions, so this is how the downloader
 # thread learns why a file is still missing
@@ -124,7 +128,9 @@ class ModelDownloader:
             logger.info(f"Downloading model file from: {url}")
 
         try:
-            with requests.get(url, stream=True, allow_redirects=True) as r:
+            with requests.get(
+                url, stream=True, allow_redirects=True, timeout=DOWNLOAD_TIMEOUT
+            ) as r:
                 r.raise_for_status()
                 with open(temporary_filename, "wb") as f:
                     for chunk in r.iter_content(chunk_size=8192):