Alerts configuration UI

[VladimirAkopyan]

We always meant to have alerts and their configuration. However we never managed to design them properly. We do however know that proper alerts need to:

• Set Alert level, or no alert level
• Set it individually for each sensor
• Mute Alerts on a Specific Sensor
• Actually raise the damn Alert, probably as a toast.
• The alert stays until it's dismissed

[VladimirAkopyan]

It's probably best to bring back the alerts buttons on the card, that was cool. However, we probably don;t need alerts side bar for now, just toast. That's because I'd like to re-work the API before syncing alerts across different computers. Let's just toast it for now.