Move usages of Settings Tray in themes

Problem/Motivation

$ git grep settings_tray| grep themes 
core/themes/default_admin/default_admin.libraries.yml:    - default_admin/settings_tray
core/themes/default_admin/default_admin.libraries.yml:    - default_admin/settings_tray_edit
core/themes/default_admin/default_admin.libraries.yml:    - default_admin/settings_tray_edit
core/themes/default_admin/default_admin.libraries.yml:settings_tray:
core/themes/default_admin/default_admin.libraries.yml:      migration/css/components/settings_tray.css: { minified: false }
core/themes/default_admin/default_admin.libraries.yml:settings_tray_edit:
core/themes/default_admin/default_admin.libraries.yml:      migration/css/components/settings_tray_edit.css: { minified: false }
core/themes/stable9/stable9.info.yml:  settings_tray/drupal.settings_tray:
core/themes/stable9/stable9.info.yml:        css/settings_tray.module.css: css/settings_tray/settings_tray.module.css
core/themes/stable9/stable9.info.yml:        css/settings_tray.motion.css: css/settings_tray/settings_tray.motion.css
core/themes/stable9/stable9.info.yml:        css/settings_tray.toolbar.css: css/settings_tray/settings_tray.toolbar.css
core/themes/stable9/stable9.info.yml:        css/settings_tray.theme.css: css/settings_tray/settings_tray.theme.css

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

Introduced terminology

API changes

Data model changes

Release notes snippet