use hermesllm in arch gateway for both stream and non stream messages

tests/rest/api_llm_gateway.rest

@@ -75,3 +75,48 @@ x-arch-llm-provider-hint: gpt-3.5-turbo-0125
     }
   ]
 }
+
+### llm gateway request with function calling (default target)
+POST {{llm_endpoint}}/v1/chat/completions HTTP/1.1
+Content-Type: application/json
+
+{
+  "stream": true,
+  "model": "None",
+  "messages": [
+    {
+      "role": "user",
+      "content": "how is the weather in seattle"
+    }
+  ],
+  "tools": [
+    {
+      "type": "function",
+      "function": {
+        "name": "get_current_weather",
+        "description": "Get current weather at a location.",
+        "parameters": {
+          "type": "object",
+          "properties": {
+            "location": {
+              "type": "string",
+              "description": "The location to get the weather for",
+              "format": "City, State"
+            },
+            "unit": {
+              "type": "string",
+              "description": "The unit to return the weather in.",
+              "enum": ["celsius", "fahrenheit"],
+              "default": "celsius"
+            },
+            "days": {
+              "type": "string",
+              "description": "The number of days for the request."
+            }
+          },
+          "required": ["location", "days"]
+        }
+      }
+    }
+  ]
+}