Feature request (for discussion) add negative Carbs input

[Philoul]

Use case: sometimes (due to exercise, type of carbs during meal...) Carbs absorption can be much faster than calculated COB with deviation. So we can have for a long duration zero deviation, a lot of remaining COB and slow carbs absorption calculated by min_5m_carbimpact. This can lead to over correction on BG variation due to an overestimation of remaining COB. In parallel lots of users don't enter carbs during exercise (again to not take the risk of over correction with loop). The idea is to allow negative carbs entry (max allowed value is remaing COB), to reduce remaining COB. => for discussion...