feat(bookstack) : add BookStackConfiguration entity and repository

src/Repository/BookStackConfigurationRepository.php

@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Repository;
+
+use App\Entity\BookStackConfiguration;
+use Doctrine\Bundle\DoctrineBundle\Repository\ServiceEntityRepository;
+use Doctrine\Persistence\ManagerRegistry;
+
+class BookStackConfigurationRepository extends ServiceEntityRepository
+{
+    public function __construct(ManagerRegistry $registry)
+    {
+        parent::__construct($registry, BookStackConfiguration::class);
+    }
+
+    public function findSingleton(): ?BookStackConfiguration
+    {
+        return $this->findOneBy([]);
+    }
+}