docs for hook_entity_base_field_info()/hook_entity_base_field_info_alter()/hook_entity_bundle_field_info()/hook_entity_bundle_field_info_alter() should say how they work with base_field_override config entities

Problem/Motivation

EntityFieldManager invokes the base field hooks before it loads base_field_override config entities, so anything in the base_field_override overrides the base field hooks.

However, EntityFieldManager invokes the bundle field hooks after base_field_override config entities have been applied, so these hooks can override and alter the base_field_override config entities.

This should all be documented in the docs for these hooks.

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet