Allow placing inline blocks into the Entity Form Layout configuration

As I see we store the settings in the third-party settings of the entity form display like this:

 third_party_settings:
   field_layout:
    id: layout_threecol_25_50_25
    settings:
      label: ''

So seems we can store there the full layout with sections and blocks too.

We can implement a new block type "FieldWidgetBlock" like "FieldBlock" and use a native Layout Builder UI to place these FieldWidget blocks and all other block types.

The Field Layout Module was approved for removal in 📌 [META] Enable layout builder for form displays, and deprecate field_layout Postponed .

This is Postponed. The status is set according to two policies. The Remove a core extension and move it to a contributed project → and the Extensions approved for removal → policies.

The deprecation work is in 📌 [meta] Tasks to deprecate the Field Layout module Active and the removal work in 📌 [12.x] [meta] Tasks to remove Field Layout module Postponed .

Field Layout will be moved to a contributed project after the Drupal 12.x branch is open.