[feature] Add Phase I Ocean Observations to NOC STAC

[oj-tooth]

Add Phase I Gridded Ocean Observations for Numerical Model Validation to NOC STAC

Actions

• Create a new create_obs_item_from_icechunk_asset() utility function to create STAC Items for ocean observation datasets using global CF attributes.
• Update OceanDataCatalog filter, search methods to support searching ocean observations.
• Update OceanDataCatalog open_repo and open_dataset methods to support opening & subsetting ocean observations.
• Update __repr__ and __repr_html__ to handle numerical model and observational datasets differently - rendering different properties in summary views.