Adopt Swift Tracing

[0xTim]

Swift Tracing is now 1.0 so we should adopt it, probably in middleware to make is easy to add.

We need to be careful as it relies on TLVs so if we cross ELF boundaries we could lose the context, but I think we're ok if we use an async middleware. Will need to test the whole stack

[slashmo]

@0xTim Glad to see this being tracked now 👍 Feel free to ping me once you're starting the implementation, then I could update my HTTP client/server example to use Vapor as well as Hummingbird: https://github.com/slashmo/swift-otel/tree/example/http