Avoid alerts poping in the screen

I am pretty sure alter (like a new scan) poping in middle of the screen will fastly became annoying for people.

• This can pop over useful information
• You probably already know that something is scanning (cause most probably you have requested it)
• There is other state widget to show there is a scan

It would be good to find a way to get ride of it:

1. Maybe a scan is not an alert
2. Maybe scan alert could be disabled by configuration in some layouts
3. Maybe we could avoid scan alert if the scan was requested by this specific Daiquiri client
4. Maybe we could create a "sequencer object" with a state (like any hardware object), and so what we can display a SCANNING state

I can't tell for now, but 4. and 2. would be anyway useful.