ArangoDB/AQL support for Graph QA Chain (#7880)

**Description**: Serves as an introduction to LangChain's support for
[ArangoDB](https://github.com/arangodb/arangodb), similar to
https://github.com/hwchase17/langchain/pull/7165 and
https://github.com/hwchase17/langchain/pull/4881

**Issue**: No issue has been created for this feature

**Dependencies**: `python-arango` has been added as an optional
dependency via the `CONTRIBUTING.md` guidelines
 
**Twitter handle**: [at]arangodb

- Integration test has been added
- Notebook has been added:
[graph_arangodb_qa.ipynb](https://github.com/amahanna/langchain/blob/master/docs/extras/modules/chains/additional/graph_arangodb_qa.ipynb)

[![Open In
Collab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/github/amahanna/langchain/blob/master/docs/extras/modules/chains/additional/graph_arangodb_qa.ipynb)

```
docker run -p 8529:8529 -e ARANGO_ROOT_PASSWORD= arangodb/arangodb
```

```
pip install git+https://github.com/amahanna/langchain.git
```

```python
from arango import ArangoClient

from langchain.chat_models import ChatOpenAI
from langchain.graphs import ArangoGraph
from langchain.chains import ArangoGraphQAChain

db = ArangoClient(hosts="localhost:8529").db(name="_system", username="root", password="", verify=True)

graph = ArangoGraph(db)

chain = ArangoGraphQAChain.from_llm(ChatOpenAI(temperature=0), graph=graph)

chain.run("Is Ned Stark alive?")
```

---------

Co-authored-by: Bagatur <baskaryan@gmail.com>

docs/extras/integrations/providers/arangodb.mdx

@@ -0,0 +1,23 @@
+# ArangoDB
+
+>[ArangoDB](https://github.com/arangodb/arangodb) is a scalable graph database system to drive value from connected data, faster. Native graphs, an integrated search engine, and JSON support, via a single query language. ArangoDB runs on-prem, in the cloud – anywhere.
+
+## Dependencies
+
+Install the [ArangoDB Python Driver](https://github.com/ArangoDB-Community/python-arango) package with
+```bash
+pip install python-arango
+```
+
+## Graph QA Chain
+
+Connect your ArangoDB Database with a Chat Model to get insights on your data. 
+
+See the notebook example [here](/docs/modules/chains/additional/graph_arangodb_qa.html).
+
+```python
+from arango import ArangoClient
+
+from langchain.graphs import ArangoGraph
+from langchain.chains import ArangoGraphQAChain
+```