[meta] Tasks to remove Field Layout module

Problem/Motivation

Track the steps needed to remove extension Field Layout from core to contrib. See Remove a core module and move it to a contributed project of the deprecation policy.

The removal of extension Field Layout was approved in #3007167: [policy] Deprecate field_layout module and move it to contrib.

Remaining tasks

1. Create a child issue, 'Remove Field Layout from core'.
   • ✅ The change record for this issue should include a link to recommendations page, https://www.drupal.org/node/3223395#s-field-layout. (For example, the CR for removing HAL)
   • Tag this issue 'Needs release note.'
   • Remove the extension ;-).
   • Update Update path tests as needed. See Writing Automated Update Tests for Drupal 8 (or later) for details.
   • Remove references from core/phpstan-baseline.neon.
   • Remove any spelling words specific to the extension from the dictionary
   • Add the extension to the relevant removed list, either DRUPAL_CORE_REMOVED_MODULE_LIST or DRUPAL_CORE_REMOVED_THEME_LIST, in system.install.
   • Check for references in @todo.
   • Handle migration tests.
     • In all the functional tests in migrate_drupal_ui make sure that Field Layout is not installed. EXTENSION_NAME should also be removed from the methods getAvailablePaths() and moved to getMissingPaths() in the tests using those methods.
2. ✅ Deprecate the extension in the current minor development branch. If the next major branch is open, the extension can be removed via a separate patch (to avoid dependent patches), otherwise an issue should be opened to remove the extension once the next major branch is open.
3. ✅ Open an issue, 'Ensure that Field Layout does not get special core treatment' in the packages.drupal.org issue queue to ensure that the composer namespace for the contributed project matches the core one after removal. This is to allocate the drupal/Field Layout Composer namespace to contrib extension rather than the core extension.
4. ✅ Manually test upgrading from the core extension to the contrib extension. There is an issue template available for this.
5. ✅ Triage core issues for Field Layout in the core queue and move either to the contrib project or the relevant core component. Restore the status to what it was before it was postponed. Also, is the issue moved to contrib, then move any change record.
6. ✅ Move all core documentation for Field Layout to the contrib project. Make issues in the contrib project to update or add links to the documentation on the project page.
7. ✅ When the issue in https://www.drupal.org/project/project_composer is Fixed update the documentation with the new Composer command.

Release notes snippet