performance-monitoring

To boost the minification we have some mangle properties in the Terser config.
https://github.com/Zizzamia/perfume.js/blob/master/rollup.config.ts

But over time we stopped using most of them, I think it's time to double-check which one are the properties are not necessary anymore.

Description

The new APM guide doesn't contain the transaction metrics that are generated in the APM Server which power the APM UI. We still have them in the legacy documentation https://github.com/elastic/apm-server/blob/master/docs/legacy/metricset-indices.asciidoc#transaction-metrics.

Ideally we should port most if not all of the document's content over to the data model document: https

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

The .. module has a conditional dependency on the parseurl library. This library is not an agent dependency. However, if parseurl is present then the agent will use it instead of it's own home grown URL parsing.

We've had users report that this conditional `re