Record TCP connection local socket address in metadata (#3286)

## Motivation and Context
I want to use this field to uniquely identify TCP connection based on
their `local_addr` + `remote_addr`.

See https://github.com/awslabs/aws-sdk-rust/issues/990 for additional
motivation for this change.

## Description
- Add a new optional `local_addr` field in the `ConnectionMetadata`
struct.
- Transfer the `local_addr` `SocketAddress` from the `hyper::HttpInfo`
to the `ConnectionMetadata` field.
- Add to the `trace-serialize` example program so that it will print out
the capture connection values.

## Testing
`cargo test` in `rust-runtime/aws-smithy-runtime-api` and
`aws-smithy-runtime`.

Also ran:
```
thedeck@c889f3b04fb0 examples % cargo run --example trace-serialize
    Finished dev [unoptimized + debuginfo] target(s) in 0.13s
     Running `/Users/thedeck/repos/github/declanvk/smithy-rs/target/debug/examples/trace-serialize`
2023-12-06T00:13:15.605555Z  INFO lazy_load_identity: aws_smithy_runtime::client::identity::cache::lazy: identity cache miss occurred; added new identity (took Ok(296µs))
2023-12-06T00:13:15.608344Z  INFO trace_serialize: Response received: response=Response { status: StatusCode(200), headers: Headers { headers: {"content-type": HeaderValue { _private: "application/json" }, "content-length": HeaderValue { _private: "17" }, "date": HeaderValue { _private: "Wed, 06 Dec 2023 00:13:15 GMT" }} }, body: SdkBody { inner: BoxBody, retryable: false }, extensions: Extensions }
2023-12-06T00:13:15.608388Z  INFO trace_serialize: Captured connection info remote_addr=Some(127.0.0.1:13734) local_addr=Some(127.0.0.1:50199)
2023-12-06T00:13:15.608511Z  INFO trace_serialize: Response received POKEMON_SERVICE_URL=http://localhost:13734

 response=GetServerStatisticsOutput { calls_count: 0 }
```

You can see the log line with "Captured connection info" contains the
`remote_addr` and the `local_addr` fields.

## Checklist
- [x] I have updated `CHANGELOG.next.toml` if I made changes to the AWS
SDK, generated SDK code, or SDK runtime crates

----

_By submitting this pull request, I confirm that you can use, modify,
copy, and redistribute this contribution, under the terms of your
choice._

Co-authored-by: Declan Kelly <thedeck@amazon.com>