OpenTelemetry Semantic Conventions

[bpholt]

Should the trace attributes added by this library follow OpenTelemetry semantic conventions? For example,

natchez-http4s/modules/http4s/src/main/scala/natchez/http4s/NatchezMiddleware.scala

Lines 176 to 177 in 659d412

	"client.http.uri" -> req.uri.toString(),
	"client.http.method" -> req.method.toString

should be url.full and http.request.method, respectively, and

natchez-http4s/modules/http4s/src/main/scala/natchez/http4s/NatchezMiddleware.scala

Line 183 in 659d412

_ <- Trace[F].put("client.http.status_code" -> rsrc._1.status.code.toString())

should be http.response.status_code.