[DOP-29492] Implement Iceberg.DelegatedWarehouse

[dolfinus]

Change Summary

Some Iceberg REST Catalog implementations (Lakekeeper, Polaris, Gravitino) can use only vended S3 credentials and warehouse path, ignoring user specified params. Implemented new Iceberg.DelegatedWarehouse class for that.

https://onetl--413.org.readthedocs.build/en/413/connection/db_connection/iceberg/warehouse_delegated.html

Related issue number

Checklist

• Commit message and PR title is comprehensive
• Keep the change as small as possible
• Unit and integration tests for the changes exist
• Tests pass on CI and coverage does not decrease
• Documentation reflects the changes where applicable
• docs/changelog/next_release/<pull request or issue id>.<change type>.rst file added describing change
  (see CONTRIBUTING.rst for details.)
• My PR is ready to review.

[github-actions]

Coverage Report •

File	Stmts	Miss	Cover	Missing
onetl/connection/db_connection/iceberg
connection.py	202	30	85%	341–343, 498–500, 502–503, 505–507, 517, 519–520, 536–537, 539–542, 544–546, 548, 591–593, 595, 597, 612
onetl/connection/db_connection/iceberg/warehouse
filesystem.py	27	1	96%	114
onetl/connection/file_df_connection/spark_s3
connection.py	156	3	98%	431–432, 447
TOTAL	9965	289	97%