Updated nasa-nex-gddp-cmip6

[TomAugspurger]

Description

This adds a new dataset for the nasa-nex-gddp-cmip6 Colleciton.

Previously, these STAC items were created out of band and imported as pre-made items. Now we'll create them in the workflow. The summary of the changes:

1. Use the stactools package, which has been updated to handle v1.1 and v1.2 assets from the upstream data source
2. Generate the items within pctasks
3. Add a separate workflow for Kerchunk

How Has This Been Tested?

STAC item creation has been tested with

pushd datasets/nasa-nex-gddp-cmip6-netcdf
pytest

The workflow has been tested up to ingestion with

$ pctasks dataset process-items -d datasets/nasa-nex-gddp-cmip6-netcdf/dataset.yaml --no-ingest -su 2024.4.12.0

The output can be viewed under https://nasagddp.blob.core.windows.net/nex-gddp-cmip6-etl-data/pctasks/2024.4.12.0/items/all/nasagddp/nex-gddp-cmip6/NEX/GDDP-CMIP6/

The Kerchunk workflow has been tested with

$ pctasks workflow upsert-and-submit datasets/nasa-nex-gddp-cmip6-netcdf/kerchunk-workflow.yaml --arg registry pccomponents.azurecr.io --arg prefix "blob://nasagddp/nex-gddp-cmip6/NEX/GDDP-CMIP6/" --arg references_prefix "https://nasagddp.blob.core.windows.net/nex-gddp-cmip6-references/test"

Checklist:

Please delete options that are not relevant.

• I have performed a self-review
• Changelog has been updated
• Documentation has been updated
• Unit tests pass locally (./scripts/test)
• Code is linted and styled (./scripts/format)