Add phpinfo page

Since Raspberry Pi isn't a high-end Device we might to change some
settings inside php.ini to use resource-hungry functions as
e.g. photo collage.

On the PHP Info Page take a look for "Loaded Configuration File"
to see where your php.ini is located.

phpinfo.php

@@ -0,0 +1,3 @@
+<?php
+phpinfo();
+?>