[demos] Serve the batch-analytics TPC-H data from a live bucket - #6781

AWS disabled s3://batchtofeldera along with the account that owned it, so every
read answers 403 AllAccessDisabled. That breaks the accelerating-batch-analytics
packaged demo for anyone who opens it in the Web Console, and fails the
"Validate and run packaged demos" step in CI.

This points the demo, the TPC-H workload tests, and the batch use-case docs at
s3://feldera-demo-datasets/tpch/sf0.1 in us-west-1.

The bucket is provisioned as code with anonymous GetObject and ListBucket, so
readers still need no credentials and aws_skip_signature keeps working.

The replacement carries the same scale factor as the old bucket, so the record
counts in the tutorial are unchanged (lineitem 601k, customer 15.0k, ...).

scripts/tpch_demo_data.py regenerates the data from the official TPC-H dbgen
(v2.17.3). Scale factors 0.01, 0.1 and 1 are published under tpch/sf<N>/.

Describe Manual Test Plan

• Generated all three scale factors with the official dbgen and confirmed the
  canonical TPC-H cardinalities (sf1: lineitem 6,001,215, orders 1,500,000;
  sf0.1: lineitem 600,572, customer 15,000).
• Confirmed the Delta schema matches the demo's CREATE TABLE: integer,
  decimal(15,2), date, string, with only n_comment and r_comment
  nullable.
• Read all 8 tables from S3 with every AWS credential stripped from the
  environment, mirroring how the connector reads them.
• Verified anonymous LIST and GET over plain HTTPS return 200.

Checklist

• Unit tests added/updated
• Integration tests added/updated
• Documentation updated
• Changelog updated

Breaking Changes?

• OpenAPI / REST HTTP API / feldera-types / manager
• Feldera SQL (Syntax, Semantics)
• feldera-sqllib
• Python SDK
• fda (CLI arguments)
• Adapters (including configuration)
• Storage Format / Checkpoints
• Others (specify)

Describe Incompatible Changes

None. The demo's SQL schema and the tutorial's record counts are unchanged; only
the bucket the data is served from differs.