* Add http.route.
* Align all fields with OpenTelemetry's semantic conventions.
* Add span kind.
* Emit event for errors.
Add OTEL status code.
* Create otel.status_code field as empty.
* Fix errors.
* Add (feature-gated) support for OpenTelemetry span propagation.
* Capture the trace id as an attribute on the span.
* Change message.
* Log the newly-generated trace id if there is no parent context.
* Define a root_span macro as a stepping stone to allow crate users to add their own fields to the root span.
* Add comments.
* mut is no longer necessary.
* Allow users to customise generation of the root span. Split recording fields on span end from emission of log record. Make log record on error optional via feature flag.
* Provide constructor + default implementation.
* Explode into multiple modules.
Fix various paths/private imports in root_span.
* Rename module to root_span_macro.
* Add a new extractor to retrieve the root span.
* Document crate.
* Docs!
* Add section on OTEL.
* Mention actix-web-opentelemetry.
* Add OpenTelemetry example.
* Improve readme.
* Add custom root span example.
Co-authored-by: LukeMathWalker <contact@palmieri.com>
