Support HTTP resumable upload.
### Motivation:
Supporting HTTP resumable upload protocol defined in
https://datatracker.ietf.org/doc/html/draft-ietf-httpbis-resumable-upload-05
* Interop version 3: iOS 17.0, macOS 14.0
* Interop version 5: iOS 18.0, macOS 15.0
* Interop version 6: iOS 18.1, macOS 15.1
### Modifications:
2 new public classes, `HTTPResumableUploadHandler` and
`HTTPResumableUploadContext`, and a few other supporting objects to
manage resumable uploads and translate them into regular uploads.
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Co-authored-by: Jonathan Flat <jflat@apple.com>
Co-authored-by: Cory Benfield <lukasa@apple.com>
