Status message modernization

Thank you @froboy
These "modal bothering popup statuses" in Carnation always drive me crazy
We should work on getting better and more consistent UX for them
Probably to leverage same UX as we do for Alerts to make them consistent across the site.

@podarok yup, but I think a much more straightforward solution will get us what we need. I've converted the code in status-messages.html.twig to remove the modal and use the standard Bootstrap alert styles. With a little off-canvas styles this makes alerts consistent in both the main pages and the sidebar, and means no more requirement of clearing all of the alerts to get back to work.

Automatically closed - issue fixed for 2 weeks with no activity.