Reference - Update REST API docs

[pavithraes]

Create a REST API reference at: https://conda.store/conda-store/references/api

Tasks:

• Integrate a plugin for openapi <> docusaurus (blocked - currently, the plugin in not compatible with docusaurus v3)
• Create a GH action to generate openapi.json regularly for keeping the reference up-to-date

[peytondmurray]

We have openapi docs that work at the moment; let's revisit later if folks want to have more robust REST api docs.