Notification when recommendations capped

[gempickfordwaugh]

During looping, sometimes the loop is hitting some security settings (preferences like max_basal, max_iob, max_daily_safety_multiplier, current_basal_safety_multiplier) and the right amount of insulin for corrections is capped. An alarm or notification for when the cap is reached and how much has been missed when this happens would be really helpful. Bonus features would include stating which preference is limiting the Loop (or option to choose only one of them), what the current autosens value/ratio is and length of time cap has been reached.

Linked to open issue in AndroidAPS https://github.com/MilosKozak/AndroidAPS/issues/347 which could be supported if determine-basal would put a flag in the result object which could trigger an alarm.

[scottleibrand]

Like #787, this probably depends on #789 for OpenAPS. Will comment in https://github.com/MilosKozak/AndroidAPS/issues/347 about getting the data to AndroidAPS.