Add interfaces to provide problem information

Author: lcobucci

src/Problem/Detailed.php

@@ -0,0 +1,14 @@
+<?php
+declare(strict_types=1);
+
+namespace Lcobucci\ErrorHandling\Problem;
+
+use Throwable;
+
+interface Detailed extends Throwable
+{
+    /**
+     * @return array<string, mixed>
+     */
+    public function getExtraDetails(): array;
+}

src/Problem/Titled.php

@@ -0,0 +1,11 @@
+<?php
+declare(strict_types=1);
+
+namespace Lcobucci\ErrorHandling\Problem;
+
+use Throwable;
+
+interface Titled extends Throwable
+{
+    public function getTitle(): string;
+}

src/Problem/Typed.php

@@ -0,0 +1,11 @@
+<?php
+declare(strict_types=1);
+
+namespace Lcobucci\ErrorHandling\Problem;
+
+use Throwable;
+
+interface Typed extends Throwable
+{
+    public function getTypeUri(): string;
+}