opentelemetry-instrumentation-tornado: reduce cardinality of span names and metrics attributes (#4577)

* opentelemetry-instrumentation-tornado: reduce cardinality of telemetry

Reduce metrics cardinality for new stable path by dropping the usage or
URL_PATH and URL_QUERY in favor of HTTP_ROUTE.

* Reduce cardinality on server span name

* Add changelog

* Fix lint

* On 404 just use the method as span name

* Return a low cardinality route for routes with regex but not groups