Add interface RequestBody to encapsulate bodies that can be replayed and those that can't

[bmoylan]

Our handling of streaming request bodies is currently incorrect. We accept a func() io.ReadCloser, but assume this function can be called multiple times. In practice, some bodies are streamed from sources that can't be reconstructed or retrieved again without additional handling.

In this PR we introduce the RequestBody interface, implemented by 3 exported constructor functions:

• RequestBodyInMemory for payloads of known types that can be easily reset
• RequestBodyStreamOnce for payloads that can not be reset
• RequestBodyStreamWithReplay for arbitrary functions that return readers but can be called multiple times to generate new bodies.

After this merges, I plan to update conjure-go's generated client interfaces. Those that currently have a bodyArg func() io.ReadCloser will instead have bodyArg httpclient.RequestBody and the caller can decide what to provide.

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Type

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Description

Add interface RequestBody to encapsulate bodies that can be replayed and those that can't **Check the box to generate changelog(s)** - [x] Generate changelog entry