Add documentation on each Dioptra service

[keithmanville]

Describe how each Dioptra service runs (what are the necessary dependencies) and how it interacts with other services.

e.g. environment variables needed by flask service (or any other service), flask requiring a database (either postgres or sqlite which doesn't need a formal service), flask depending on redis and a worker to run jobs.

services:

• Dioptra REST API
• Dioptra Worker
• MLflow Tracking Server
• Database (sqlite, postgres) - Can be externally managed
• Object storage (Minio, AWS S3) - Can be externally managed
• In-memory key-value store (Redis) - Can be externally managed

A description of each service allows use to define different deployment environments.

example environments:

1. Development (containerless)
2. Local deployment
3. Cloud / Distributed

The documentation should be a combination of description and diagrams showing the interactions between services.

One option for creating diagrams is Mermaid. There is a sphinx plugin: https://github.com/mgaitan/sphinxcontrib-mermaid

Definition of Done

• All services listed above are documented in rst and built into the sphinx docs
• New documentation is merged into dev