Add option to customize user agents in robots.txt

module/Core/src/Options/RobotsOptions.php

@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Shlinkio\Shlink\Core\Options;
+
+use function count;
+
+final readonly class RobotsOptions
+{
+    public function __construct(
+        public bool $allowAllShortUrls = false,
+        /** @var string[] */
+        public array $userAgents = [],
+    ) {
+    }
+
+    public function hasUserAgents(): bool
+    {
+        return count($this->userAgents) > 0;
+    }
+}