Use AtCore::StatusWidget

Summary:
Use AtCore::StatusWidget for the status area on AtCoreInstances

This removes the print progress widget and uses the AtCore::StatusWidget.. This provides the status, and when printing our progress bar as well as the time and remaining time.

Reviewers: laysrodrigues, patrickelectric, tcanabrava

Reviewed By: patrickelectric

Subscribers: Atelier: General Development

Tags: Atelier: General Development

Differential Revision: https://phabricator.kde.org/D12203