Memtierd demo

[luukasmakila]

The demo showcases the benefits of using Memtierd as a memory manager for your workloads.

Summary of changes:

• Added the demo/ directory. Future demos can also be stored there.
• Added demo/memtierd directory to hold all the Memtierd demo related files.
• Added demo/memtierd/main.py. This is a small API made with Python and FastAPI. It accepts requests from Grafana, reads the requested data from where the memtierd NRI plugin is writing it and then returns the data in correct format.
• Added demo/memtierd/memtierd-demo-grafana-dashboard.json. This is a JSON model of the Grafana dashboard and is generated by Grafana. It can be used to easily copy the dashboard used for the demo.
• Added a picture of the Grafana dashboard.
• Added a README.md and docs to replicating the demo.

[marquiz]

Let's merge this and improve later if needed?

[klihub]

Closing this as outdated. We can update and reopen it later if it should be considered for inclusion.