Rename custom module directories

- Rename `opdavies_blog` to `blog`.
- Rename `opdavies_blog_test` to `blog_test`.
- Rename `opdavies_talks` to `talks`.
- Rename `opdavies_talks_test` to `talks_test`.

The files within the directories haven't changed, so there is no
breaking change caused by renaming the directories.

 Please enter the commit message for your changes. Lines starting

web/modules/custom/blog/src/Command/ExportBodyValuesForThemePurgingCommand.php

@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\opdavies_blog\Command;
+
+use Drupal\Core\Database\Connection;
+use Illuminate\Support\Collection;
+
+final class ExportBodyValuesForThemePurgingCommand {
+
+  private static array $tableNames = [
+    'block_content__body',
+    'node__body',
+  ];
+
+  private string $filename = 'body-field-values.txt';
+
+  private Connection $database;
+
+  public function __construct(Connection $database) {
+    $this->database = $database;
+  }
+
+  /**
+   * Drush command to export body field values into a file.
+   *
+   * @command opdavies:export-body-values-for-theme-purging
+   */
+  public function handle(): void {
+    $values = Collection::make(self::$tableNames)
+      ->flatMap(fn(string $tableName) => $this->getValuesFromTable($tableName))
+      ->implode(PHP_EOL);
+
+    file_put_contents($this->getFilePath(), $values);
+  }
+
+  private function getFilePath(): string {
+    return drupal_get_path('theme', 'opdavies') . DIRECTORY_SEPARATOR . $this->filename;
+  }
+
+  private function getValuesFromTable(string $tableName): array {
+    return $this->database->select($tableName)
+      ->fields($tableName, ['body_value'])
+      ->execute()
+      ->fetchCol();
+  }
+
+}