Add UnmarshalXML methods that set the internal 'set' flag during XML
parsing. Previously these flags were only set programmatically, causing
XML round-trip to drop elements. This ensures lifecycle configurations
stored as XML survive unmarshal/marshal cycles correctly.
Add comprehensive XML round-trip tests for all lifecycle rule types
including NoncurrentVersionExpiration, AbortIncompleteMultipartUpload,
Filter with Tag/And/size constraints, and a complete Terraform-style
lifecycle configuration.
Add missing S3 lifecycle rule types to the XML data model:
- NoncurrentVersionExpiration with NoncurrentDays and NewerNoncurrentVersions
- NoncurrentVersionTransition with NoncurrentDays and StorageClass
- AbortIncompleteMultipartUpload with DaysAfterInitiation
- Filter.ObjectSizeGreaterThan and ObjectSizeLessThan
- And.ObjectSizeGreaterThan and ObjectSizeLessThan
- Filter.UnmarshalXML to properly parse Tag, And, and size filter elements
Each new type follows the existing set-field pattern for conditional
XML marshaling. No behavior changes - these types are not yet wired
into handlers or the lifecycle worker.