<!-- .github/pull_request_template.md -->
## Description
This PR adds support for the Memgraph graph database following the
[graph database integration
guide](https://docs.cognee.ai/contributing/adding-providers/graph-db/graph-database-integration):
- Implemented `MemgraphAdapter` for interfacing with Memgraph.
- Updated `get_graph_engine.py` to return MemgraphAdapter when
appropriate.
- Added a test script:` test_memgraph.py.`
- Created a dedicated test workflow:
`.github/workflows/test_memgraph.yml.`
## DCO Affirmation
I affirm that all code in every commit of this pull request conforms to
the terms of the Topoteretes Developer Certificate of Origin.
---------
Co-authored-by: Vasilije <8619304+Vasilije1990@users.noreply.github.com>
Co-authored-by: Boris <boris@topoteretes.com>
