Neo4j conversation cypher template (#12927)

Adding custom graph memory to Cypher chain

---------

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

templates/neo4j-cypher-memory/ingest.py

@@ -0,0 +1,16 @@
+from langchain.graphs import Neo4jGraph
+
+graph = Neo4jGraph()
+
+graph.query(
+    """
+MERGE (m:Movie {name:"Top Gun"})
+WITH m
+UNWIND ["Tom Cruise", "Val Kilmer", "Anthony Edwards", "Meg Ryan"] AS actor
+MERGE (a:Actor {name:actor})
+MERGE (a)-[:ACTED_IN]->(m)
+WITH a
+WHERE a.name = "Tom Cruise"
+MERGE (a)-[:ACTED_IN]->(:Movie {name:"Mission Impossible"})
+"""
+)