Create a userscript to add an upload button to stash

[bdbenim]

Either create a second userscript or extend the functionality of the existing userscript to add an upload button to stash's UI. This button will trigger a job to start as in #128 before navigating the user to upload.php. If possible, pre-populate the upload form with the result of the job. If not, a menu can be displayed to the user allowing them to select the job to retrieve.