* it compiles
* refactored
* reduce to 4 concurrent chunk upload
* CopyObjectPartHandler
* copy a range of the chunk data, fix offset size in copied chunks
* Update s3api_object_handlers_copy.go
What the PR Accomplishes:
CopyObjectHandler - Now copies entire objects by copying chunks individually instead of downloading/uploading the entire file
CopyObjectPartHandler - Handles copying parts of objects for multipart uploads by copying only the relevant chunk portions
Efficient Chunk Copying - Uses direct chunk-to-chunk copying with proper volume assignment and concurrent processing (limited to 4 concurrent operations)
Range Support - Properly handles range-based copying for partial object copies
* fix compilation
* fix part destination
* handling small objects
* use mkFile
* copy to existing file or part
* add testing tools
* adjust tests
* fix chunk lookup
* refactoring
* fix TestObjectCopyRetainingMetadata
* ensure bucket name not conflicting
* fix conditional copying tests
* remove debug messages
* add custom s3 copy tests
