* test(s3tables): add Apache Doris Iceberg catalog integration test
Adds an end-to-end smoke test that boots the apache/doris all-in-one
container, registers SeaweedFS as an external Iceberg REST catalog
(OAuth2 client_credentials), and validates metadata visibility plus the
parquet read path against tables seeded via the Iceberg REST API and a
PyIceberg writer container, mirroring the existing Trino, Spark, and
Dremio coverage. Wires the test into a new s3-tables-tests workflow job.
* test(s3tables): document weed shell -master flag format and fill in helper docstrings
Restores the explanatory comment on createTableBucket about the
host:port.grpcPort ServerAddress format used by `weed shell -master`
(produced by pb.NewServerAddress) so the dot separator isn't mistaken
for a typo, and adds doc comments for createIcebergNamespace,
createIcebergTable, doIcebergJSONRequest, requireDorisRuntime, and
hasDocker.