Support icechunk

[jbusecke]

Replacing #96 since we cannot deploy to sandbox from a fork.

Depends on #95 and developmentseed/titiler#1235

Tasks

• Updated zarr to v3
• Modified the test fixture scripts to write v2 and v3 zarr stores explicitly (I retriggered them and committed the new fixtures)
• Add scripts/fixtures for native icechunk
• Deploy and test on real-world native icechunk data
• Add scripts/fixtures for virtual icechunk
• Deploy and test on real-world virtual icechunk data
• Implement auth as pydantic setting
• End-to-end test with deployment
  • I want the following links to work:
    • MUR from native icechunk store
    • MUR from virtual icechunk store
    • NLDAS from virtual icechunk store
• Maybe: Write more focused test for the backend format guesser?

[jbusecke]

The deployment is failing due to git missing?.

[jbusecke]

Okay, quick update:
I’ve implemented the settings as a proper Pydantic API settings entry, but I’m still figuring out how to provide the environment variable, which would be a JSON with the appropriate AWS deployment settings (example of how I set it in the tests).
@hrodmn, any input on that would be much appreciated.

But overall, I am happy with the progress, and I am confident that I am close, since things work locally with the virtualized chunk store pointing to publicly available S3—so that’s great. 🚀

[jbusecke]

Yay, all the 3 links (top comment) work!

[jbusecke]

Still fighting with pre commit here, but I think this should be minor. Shouldn't preclude any kind of review.