Expose function available_models (#475)

* Expose function available_models

* Add test case

faster_whisper/utils.py

@@ -2,7 +2,7 @@ import logging
 import os
 import re
 
-from typing import Optional
+from typing import List, Optional
 
 import huggingface_hub
 import requests
@@ -24,6 +24,11 @@ _MODELS = {
 }
 
 
+def available_models() -> List[str]:
+    """Returns the names of available models."""
+    return list(_MODELS.keys())
+
+
 def get_assets_path():
     """Returns the path to the assets directory."""
     return os.path.join(os.path.dirname(os.path.abspath(__file__)), "assets")