Fix field cache for anonymous users by implementing LazyBuilder

Problem/Motivation

There is still a problem with page_cache module, in the sense that it NEVER refreshed the cache, even if office_hours thinks it must be done in xx minutes, due to a opening/closing time.

The core 'Comment' module implements '#lazy_builder' on 2 locations. Let us learn from that.
It might be a better alternative to the current JS refresh.

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes