Put the public directory back for the v8 api endpoint

in commit 59a76f1d54 this (v8 [NOT V8])
was marked as being "deprecated"; however, it was completely killed by
the removal of it's endpoint directory

lib/API/public/index.php

@@ -0,0 +1,5 @@
+<?php
+if (!defined('sugarEntry')) {
+    define('sugarEntry', true);
+}
+require_once __DIR__.'/../core/app.php';