templates: Add neo4j semantic layer with ollama template (#17192)

A template with JSON-based agent using Mixtral via Ollama.

---------

Co-authored-by: Erick Friis <erick@langchain.dev>

templates/neo4j-semantic-ollama/neo4j_semantic_ollama/smalltalk_tool.py

@@ -0,0 +1,39 @@
+from typing import Optional, Type
+
+from langchain.callbacks.manager import (
+    AsyncCallbackManagerForToolRun,
+    CallbackManagerForToolRun,
+)
+from langchain.pydantic_v1 import BaseModel, Field
+from langchain.tools import BaseTool
+
+response = (
+    "Create a final answer that says if they "
+    "have any questions about movies or actors"
+)
+
+
+class SmalltalkInput(BaseModel):
+    query: Optional[str] = Field(description="user query")
+
+
+class SmalltalkTool(BaseTool):
+    name = "Smalltalk"
+    description = "useful for when user greets you or wants to smalltalk"
+    args_schema: Type[BaseModel] = SmalltalkInput
+
+    def _run(
+        self,
+        query: Optional[str] = None,
+        run_manager: Optional[CallbackManagerForToolRun] = None,
+    ) -> str:
+        """Use the tool."""
+        return response
+
+    async def _arun(
+        self,
+        query: Optional[str] = None,
+        run_manager: Optional[AsyncCallbackManagerForToolRun] = None,
+    ) -> str:
+        """Use the tool asynchronously."""
+        return response