Resolve #3454417 "About the theme"

Closes #3454417

theme-settings.php

+<?php
+
+/**
+ * @file
+ * Functions to support theme settings in the UI Suite DSFR theme.
+ */
+
+/**
+ * Implements hook_form_system_theme_settings_alter().
+ */
+function ui_suite_dsfr_form_system_theme_settings_alter(&$form, $form_state, $form_id = NULL) {
+  // Work-around for a core bug affecting admin themes. See issue #943212.
+  if (isset($form_id)) {
+    return;
+  }
+
+  $form['ui_suite_dsfr_utilities'] = [
+    '#type' => 'details',
+    '#title' => t('UI Suite DSFR Utilities'),
+    '#open' => TRUE,
+  ];
+
+  $form['ui_suite_dsfr_utilities']['container'] = [
+    '#type' => 'select',
+    '#title' => t('Container'),
+    '#default_value' => theme_get_setting('container'),
+    '#description' => t('Select the type of container that will be used on your site.'),
+    '#options' => [
+      'fr-container' => t('Default'),
+      'fr-container--fluid' => t('Fluid'),
+    ],
+  ];
+  $theme = _ui_suite_dsfr_get_theme_name($form);
+  $colors = _ui_suite_dsfr_get_colors_options($theme);
+  if (isset($colors)) {
+    $form['ui_suite_dsfr_utilities']['available_colors'] = [
+      '#type' => 'select',
+      '#title' => t('Available colors'),
+      '#multiple' => TRUE,
+      '#size' => 12,
+      '#default_value' => theme_get_setting('available_colors'),
+      '#description' => t('If no selected - then all will be available. For more info visit <a href="https://www.systeme-de-design.gouv.fr/elements-d-interface/fondamentaux-de-l-identite-de-l-etat/couleurs-utilisation-dans-le-dsfr/" target="_blank">DSFR Colors</a> page.'),
+      '#options' => $colors,
+    ];
+  }
+
+  $form['ui_suite_dsfr_utilities']['logo_text'] = [
+    '#type' => 'textfield',
+    '#title' => t('Logo text for header and footer'),
+    '#default_value' => theme_get_setting('logo_text'),
+  ];
+
+  $form['ui_suite_dsfr_utilities']['dsfr_footer_top'] = _menu_settings_form(
+    t("Footer top menu"),
+    theme_get_setting('dsfr_footer_top') ?? "account"
+  );
+}