Adapters loading (#902)

* Added functionality to load in adapters through post-requests so you do not need to restart the server

* ran pre-commit

* nits

* fix test

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Co-authored-by: Awni Hannun <awni@apple.com>

llms/tests/test_server.py

@@ -12,7 +12,7 @@ class DummyModelProvider:
         HF_MODEL_PATH = "mlx-community/Qwen1.5-0.5B-Chat-4bit"
         self.model, self.tokenizer = load(HF_MODEL_PATH)
 
-    def load(self, model):
+    def load(self, model, adapter=None):
         assert model in ["default_model", "chat_model"]
         return self.model, self.tokenizer