Add support for reading from Unity catalog with Iceberg REST

[ebyhr]

Description

This PR supports only read operations because Iceberg REST interface in Unity catalog doesn't support creating tables yet.

Note that Databricks Unity catalog provides HTTP interface, but it doesn’t return Iceberg UniForm tables.

Example catalog config properties:

connector.name=iceberg
iceberg.catalog.type=rest
iceberg.rest-catalog.uri=https://dbc-12345678-9999.cloud.databricks.com/api/2.1/unity-catalog/iceberg
iceberg.security=read_only
iceberg.rest-catalog.security=OAUTH2
iceberg.rest-catalog.oauth2.token=***
iceberg.rest-catalog.parent-namespace=test_namespace

Fixes #22609

Release notes

# Iceberg
* Add support for reading from Unity catalog with REST catalog. ({issue}`22609`)

[decgowran]

@ebyhr do you know if this WIP or planning to be merged in the near future ?

[MichaelKoch]

any roadmap to merge that PR ?

[decgowran]

any roadmap to merge that PR ?

@MichaelKoch Im looking into alternative in k8s with https://github.com/duckdb/uc_catalog

[MichaelKoch]

@decgowran : thanks for the link ..
i would love to see that this PR get merged to use trino + uc
IMHO : a great partnership

[decgowran]

Hi @ebyhr Will this be available in the next Trino Release to test ?

[findinpath]

What happens when a user forgets ot set iceberg.security=read_only ?

[ebyhr]

Write operations will result in the following error:

Query 20241015_222748_00008_srrgj failed: Unable to process: Status: 405
Description: Method Not Allowed