Add aws-xray plugin

**Is your feature request related to a problem? Please describe.**

I want to add a plugin that creates xray trace segments similar to some existing plugins (newrelic, sentry, opentellemetery)

**Describe the solution you'd like**

Implement a new `@envelope/xray` package that uses `aws-xray-core` to create new trace segments for `execute` and (conditionally) resolver calls if execution is already happening inside a trace segment.

**Describe alternatives you've considered**

Using the open telemetry plugin along with AWS X-Ray Exporter for OpenTelemetry Collector, but would be nice to just create xray segments directly.

**Additional context**

Started working on a prototype here: https://github.com/dotansimha/envelop/pull/1246

I am happy to build this out unless there are any objections.