Moved config dir into app dir

Closes #1506

app/Config/setting-defaults.php

@@ -0,0 +1,22 @@
+<?php
+
+/**
+ * Default system settings.
+ *
+ * Changes to these config files are not supported by BookStack and may break upon updates.
+ * Configuration should be altered via the `.env` file or environment variables.
+ * Do not edit this file unless you're happy to maintain any changes yourself.
+ */
+
+return [
+
+    'app-name'             => 'BookStack',
+    'app-logo'             => '',
+    'app-name-header'      => true,
+    'app-editor'           => 'wysiwyg',
+    'app-color'            => '#0288D1',
+    'app-color-light'      => 'rgba(21, 101, 192, 0.15)',
+    'app-custom-head'      => false,
+    'registration-enabled' => false,
+
+];