FEATURE - BigQuery support for iceberg materialisations

[borjavb]

resolves #1370

Problem

Bigquery has now support for native iceberg tables as a new type of materialisation.

Solution

Very naive approximation on how this could look like. We support both incrementality + the desired table format.

{{ config(
    materialized="incremental",
    table_format="iceberg",
    base_location = "location"
)
}}

Checklist

• I have read the contributing guide and understand what's expected of me
• I have run this code in development and it appears to resolve the stated issue
• This PR includes tests, or tests are not required/relevant for this PR
• This PR has no interface changes (e.g. macros, cli, logs, json artifacts, config files, adapter interface, etc) or this PR has already received feedback and approval from Product or DX