feat: Add configurable S3 metadata headers to catalog

[xieandrew]

Closes #220.

Example configuration:

.ice-rest-catalog.yaml

uri: jdbc:sqlite:file:data/ice-rest-catalog/db.sqlite?journal_mode=WAL&synchronous=OFF&journal_size_limit=500
warehouse: s3://bucket1
s3:
  endpoint: http://localhost:8999
  pathStyleAccess: true
  accessKeyID: miniouser
  secretAccessKey: miniopassword
  metadata:
    x-amz-meta-expiration-seconds: "86400"
bearerTokens:
  - value: foo

[subkanthi]

LLM Review, please check if its valid

The CRT async client path does not install the `S3ObjectMetadataInterceptor`, unlike the standard sync and async paths above. When `s3.crt.enabled` is enabled, `PutObjectRequest` and `CreateMultipartUploadRequest` will therefore omit the configured `s3.metadata.*` headers, so this feature silently stops working for that supported client mode.

Please apply `applyObjectMetadataConfiguration` to the CRT builder as well, and add coverage for the CRT path if feasible.