Add VAST ads support

[grappler]

https://flowplayer.org/vast/
https://flowplayer.org/docs/vast.html
http://demos.flowplayer.org/ads/vast.html

        $vast_config = array(
            'ads' => array(
                array(
                    'time' => '',
                    'adTag' => '',
                )
            ),
        );
        $return['vast_config'] = apply_filters( 'fp5_avast_config', $vast_config, $return['id'] );

[mvarrieur]

I was just looking into this today, does the Wordpress plugin not yet support VAST? Trying to weigh my options here. I really like the plugin tho, it is super easy to use!