Owen/cleanup refactor

[OwenPriceSkelly]

closes #504 and closes #506

Overview

This was a pretty big refactor and rethinks the design of our core Garden and Entrypoint classes. I lost my original writeup to a poorly-timed browser refresh, so I synced with @WillEngler earlier talked him through the major changes.

To summarize for bookkeeping:

• "mere metadata" classes are in the schemas submodule, and are only responsible for validating data entering or exiting the system. These are EntrypointMetadata, RegisteredEntrypointMetadata, and GardenMetadata. The latter two correspond closely to the respective backend schemas
• the "interactive" classes Garden and Entrypoint are responsible for things like __call__, __dir__, _repr_html_ etc that allow users to invoke entrypoints from a garden like methods. these have a metadata attribute containing exactly one respective *Metadata object, which is required to instantiate.

This PR also declares unit test bankruptcy, but we have test czar @hholb to bail us out in #507 and #511.

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📚 Documentation preview 📚: https://garden-ai--508.org.readthedocs.build/en/508/

[codecov-commenter]

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Codecov Report

Attention: Patch coverage is 0.58366% with 511 lines in your changes missing coverage. Please review.

Project coverage is 0.13%. Comparing base (6236bd9) to head (db7ba36).

Files	Patch %	Lines
garden_ai/schemas/datacite.py	0.00%	90 Missing :warning:
garden_ai/client.py	0.00%	65 Missing :warning:
garden_ai/schemas/entrypoint.py	0.00%	62 Missing :warning:
garden_ai/app/entrypoint.py	0.00%	58 Missing :warning:
garden_ai/backend_client.py	0.00%	46 Missing :warning:
garden_ai/app/garden.py	0.00%	40 Missing :warning:
garden_ai/gardens.py	0.00%	34 Missing :warning:
garden_ai/schemas/garden.py	0.00%	31 Missing :warning:
garden_ai/entrypoints.py	0.00%	29 Missing :warning:
garden_ai/schemas/schema_utils.py	0.00%	17 Missing :warning:
... and 8 more

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HEAD has 2 uploads less than BASE

| Flag | BASE (6236bd9) | HEAD (db7ba36) | |------|------|------| ||4|2|

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #508 +/- ## ========================================== - Coverage 66.48% 0.13% -66.36% ========================================== Files 53 35 -18 Lines 3575 2240 -1335 ========================================== - Hits 2377 3 -2374 - Misses 1198 2237 +1039 ```

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[hholb]

:red_square: :red_square: :red_square: THAT DIFF :red_square: :red_square: :red_square: