Added Partner setting for enabling visibility of Advertiser data

Visibility of Adv variables for Partners is a global setting which means that all of your partners or none of your partners can access this data. Adv variables are used exclusively in the Advertiser postback/pixel to pass data from your advertiser's system to Everflow. To enable this feature, go to Control Center > Configuration > Global Settings > Edit. 

Enabling this setting allows Partners to view adv1-5 in their UI by going to Reports > Conversions.