ISTWCMS-4053: adding one column layout

src/Plugin/Layout/UwOneColumnLayout.php

+<?php
+
+namespace Drupal\uw_cfg_common\Plugin\Layout;
+
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Layout\LayoutDefault;
+use Drupal\Core\Plugin\PluginFormInterface;
+
+/**
+ * A UW one column layout.
+ *
+ * @Layout(
+ *   id = "uw_one_column",
+ *   label = @Translation("One column"),
+ *   category = @Translation("UW layouts"),
+ *   template = "templates/layout/layout--uwonecol",
+ *   regions = {
+ *     "first" = {
+ *       "label" = @Translation("Column 1"),
+ *     },
+ *   }
+ * )
+ */
+class UwOneColumnLayout extends LayoutDefault implements PluginFormInterface {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function build(array $regions) {
+
+    // Build the render array as usual.
+    $build = parent::build($regions);
+
+    return $build;
+  }
+
+}

uw_cfg_common.layouts.yml

+uw_one_column:
+  label: 'UW One column'
+  category: 'UW layouts'
+  class: '\Drupal\uw_cfg_common\Plugin\Layout\UwOneColumnLayout'
+  template: uw_fdsu_theme_resp/templates/layout/layout--uwonecol
+  default_region: first
+  regions:
+    first:
+      label: One
+  icon_map:
+    - [first]
 uw_two_column:
   label: 'UW Two columns'
   category: 'UW layouts'