API: Define an API for the core services

[MostAwesomeDude]

As a platform engineer, I want to interact datastorage, inference, configuration, and model selection via API.

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Acceptance Criteria:

• [ ] API definition to support access and configuration to the service.
• [ ] DOD version 0 met.

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References:

• Hugging Face Configuration
• ChatPDF backend

[MostAwesomeDude]

First PR is up at #67 .

[MostAwesomeDude]

This needs a bit of discussion before I take another swing at it, but I haven't forgotten.