Remove unused Product.upload/process and validate_bundle.
Remove caller of ProductUpdate.upload
Remove unused maintenance file upload translation.
Remove upload_updates route/view.
Remove unused and product update related localization string.

The last caller of this string was deleted in commit:
d501fd0368: Remove ProductUpdate.server_activate_update and disable caller
Merge pull request #630 from jrafanie/remove_product_update_upload

Remove product update upload