FEATURE: allow infinite subpages depth

resources/views/admin/content/_partials/subpages.blade.php

@@ -0,0 +1,8 @@
+<option value="{{$optionPage->id}}"
+        @if(old('parentId', $page->parentId) == $optionPage->id) selected @endif>
+    {{$prefix}} {{$optionPage->title}}
+</option>
+
+@foreach($optionPage->subpages as $subpage)
+    @include('admin.content._partials.subpages', ['optionPage' => $subpage, 'prefix' => $prefix.' - '])
+@endforeach

resources/views/admin/content/formParts/basicInformation.blade.php

@@ -43,10 +43,7 @@
             <option value="">@lang('admin/contents.noParentPage')</option>
 
             @foreach($rootPages as $rootPage)
-                <option value="{{$rootPage->id}}"
-                        @if(old('parentId', $page->parentId) == $rootPage->id) selected @endif>
-                    {{$rootPage->title}}
-                </option>
+                @include('admin.content._partials.subpages', ['optionPage' => $rootPage, 'prefix' => ''])
             @endforeach
         </select>