Remove product update upload

The old style product update uploads are no longer used.  The only update from the old days is the smart proxy and that does not get populated in the maintenance tab through "upload," it will be populated into the database from the filesystem if it exists.

I need help on removing the code in the UI as it will change the display on the maintenance tab's view template and the corresponding route.

I believe this is what's left to be removed, namely the final caller of the upload_updates method in the maintentance tab's view template:

```
git grep upload_updates
vmdb/app/views/ops/_settings_maintenance_tab.html.erb:    <%= form_tag({:action    => "upload_updates"},
```

@h-kataria @dclarizio @martinpovolny Anyone want access to my fork to push the remaining deletions?

cc @brandondunne  :see_no_evil: