added exploit module for WordPress OptimizePress Themes File Upload Vulnerability

An exploit module for the recent vulnerability in the WordPress Theme OptimizePress.

Details
Unauthenticated users can upload arbitrary files using the url
"/wp-content/themes/OptimizePress/lib/admin/media-upload.php"
The uploaded file can be reached at
"/wp-content/uploads/optpress/images_comingsoon/"

Verification
Install Wordpress and OptimizePress or test it on an alternative source ;)