Revisions: Hid changes link for oldest revision

Just as a UX improvement to help avoid confusion, as the whole content
will be changes for this revision.

For #5454

app/Entities/Controllers/PageRevisionController.php

@@ -43,7 +43,6 @@ class PageRevisionController extends Controller
             ->selectRaw("IF(markdown = '', false, true) as is_markdown")
             ->with(['page.book', 'createdBy'])
             ->reorder('id', $listOptions->getOrder())
-            ->reorder('created_at', $listOptions->getOrder())
             ->paginate(50);
 
         $this->setPageTitle(trans('entities.pages_revisions_named', ['pageName' => $page->getShortName()]));
@@ -52,6 +51,7 @@ class PageRevisionController extends Controller
             'revisions'   => $revisions,
             'page'        => $page,
             'listOptions' => $listOptions,
+            'oldestRevisionId' => $page->revisions()->min('id'),
         ]);
     }