refactor page mime routing to init multimedia support

src/Entity/Browser/Container/Page/Content/Plain.php

@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yggverse\Yoda\Entity\Browser\Container\Page\Content;
+
+class Plain extends \Yggverse\Yoda\Abstract\Entity\Browser\Container\Page\Content\Markup
+{
+    public function setSource(
+        string $value
+    ): void
+    {
+        $this->_source = $value;
+
+        $this->gtk->set_markup(
+            sprintf(
+                '<tt>%s</tt>',
+                htmlspecialchars(
+                    $value
+                )
+            )
+        );
+    }
+}