Refactor application structure, implement orchestrator with unary handling

[declark1]

This PR refactors the application structure and implements various other changes tested during our initial PoC which we will continue to iterate on, including:

• Config enhancements
• Implements Orchestrator with end-to-end unary task handling (and placeholders for streaming)
• Refactors clients (DetectorClient, NlpClient, TgisClient) to be higher-level with all methods (including streaming) fully implemented
• Custom error types
• Type conversions across APIs, e.g. generation parameters
• Updates dependencies
• Formatted and linted code (all clippy lints cleared)
• Added Dockerfile

---

TODO:

• Add doc comments to orchestrator task handlers
• Draft initial docs, including diagram illustrating the unary task processing sequence
• Improve error handling
  • Propogate errors up from all orchestrator tasks
  • Properly convert Error to appropriate http::StatusCode with context

[gkumbhat]

Thanks Dan for all the 🌶️ changes. Loving all the refactors. This is much cleaner. I went through all the files except orchestrator.rs and left some questions and comments!

[evaline-ju]

🎉 yay parallel calls! Thanks for all the cleanup here - just some q's

[evaline-ju]

LGTM

[gkumbhat]

Looks great! Thanks Dan