Move rendering into private templates

Add an explicit template renderer with HTML views and partials for the app, bootstrap, package, and catalog pages. Move shared reporting setup into config/reporting.php and relocate stylesheet assets under css/.

private/views/partials/user-delete-form.html

@@ -0,0 +1,6 @@
+<form method="post" action="/users?lang={{language_url}}"
+      onsubmit="return confirm({{{confirm_json}}});">
+<input type="hidden" name="action" value="delete_user">
+<input type="hidden" name="user_id" value="{{user_id}}">
+<button type="submit">{{delete_user_label}}</button>
+</form>