Try to avoid iterating over all bundles and fields

Problem/Motivation

We have multiple places in core where we end up iterating over all bundles of an entity, there may be places we can avoid this, or do it only where the specific bundle is actually in use on a page.

Putting this in entity system, but it's more of a problem with views, jsonapi etc. where it calls entity APIs to build metadata.

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

Introduced terminology

API changes

Data model changes

Release notes snippet