Provide easy way to parse s3://foo/bar URI into (bucket,key) pair

### Describe the feature

It is common to receive s3 object locations via a URI such as `s3://foo/bar`. It would be nice if there was some S3Url object that implements FromStr such that I can easily extract the correct bucket and object strings from such a url.

### Use Case

I'm always frustrated when I have to rewrite the same "s3 URI" to (bucket , object) parser for every CLI application I write. This involves importing one of the url or http::Uri crates and splitting hostname and path and providing appropriate error handling. Additional several times I messed up by not removing the initial `/` from the path.

It would be nice if the s3 SDK provided such tooling to make processing s3 URIs more easy.

### Proposed Solution

I think some sort of S3Uri object that implements `FromStr` would be ideal as this integrates nicely into structopt and other CLI tooling.

### Other Information

_No response_

### Acknowledgements

- [ ] I may be able to implement this feature request
- [ ] This feature might incur a breaking change

### A note for the community

### Community Note
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Start by locating the S3 URI parsing entry point and the proposed S3Url type implementing FromStr. Define the supported s3://bucket/key forms and error cases, then add tests showing the bucket and object strings are extracted without a leading slash. Done means the public parsing API supports the stated CLI use case and its behavior is covered by tests.

Written by the indexing model from the issue text.