[PS][D9] Dynamic Page Cache add in Backdrop core

This is to explore if Make D8 2x as fast: Dynamic Page Cache: context-dependent page caching (for all users!) can be applied to Backdrop and whether there is performance gain by this for us.

Relevant Drupal changerecords: - Dynamic Page Cache module added, enabled by default - Cache contexts are now hierarchical - Change all default settings and config to fast/safe production values

https://www.drupal.org/docs/8/core/modules/dynamic-page-cache/overview

Drupal 8 provides the Dynamic Page Cache module that is recommended for websites of all sizes. It caches pages minus the personalized parts, and is therefore useful for all users (both anonymous & authenticated).

We can find this core module at: core/modules/dynamic_page_cache.

Proposed solution

https://wimleers.com/article/drupal-8-dynamic-page-cache