[DX][D9] Telemetry: gather Server Timing performance metrics

This is part of the #285 meta.

Description of the need

Respective d.org issue: https://www.drupal.org/project/drupal/issues/3104566

Providing server timing would help developers estimate site performance. The corresponding W3C specification is currently in "Working Draft" status and its already supported by Google Chrome and Firefox.

https://www.w3.org/TR/server-timing/

This specification enables a server to communicate performance metrics about the request-response cycle to the user agent. It also standardizes a JavaScript interface to enable applications to collect, process, and act on these metrics to optimize application delivery.

Symfony adopted it in https://github.com/symfony/symfony/pull/27985

Proposed solution

Add Server-Timing header with relevant timing information.