Define and refine initial tasks for a cost monitoring implementation using Cost Explorer API

[consideRatio]

I'm to followup the work in #4648 by defining and refining initial tasks towards implementing monitoring usting Cost Explorer API (instead of using an Athena datasource).

Definition of done

• I've defined and refined a suitable (as determined by me) amount of work represented as github issues to be added to the engineering board.

  I'm aiming to not end up defining and refining more than I'm confident will be something I actually end up wanting to do.

Initial steps

• Create an overview of technical parts so I can consider where to start

[consideRatio]

High level tech overview

• A Python webserver
  • Python code
  • Helm based deployment, intially as a local standalone chart under helm-charts/
    • A Docker image
  • Terraform config to provide AWS resources granting relevant creds to the Python webserver deployment
• A Grafana dashboard, with various panels, with queries processing JSON responses from the Python webserver

[consideRatio]

I've created the following tasks for now, this is sufficient for now I'd say:

• Cost Explorer API (1/n): Create a Helm chart for a dummy Python webserver for use as a local support chart dependency #4670
• Cost Explorer API (2/n): Create terraform resources to provide credentials to the Python webserver #4671
• Cost Explorer API (3/n): The Python webserver to provide some relevant JSON with cost data #4672
• Cost Explorer API (4/n): A Grafana dashboard with one functional panel, processing JSON responses from the Python webserver #4673