Confidence slider default value

[alanensastegui]

I often forget to set the confidence slider before submitting my answers. I just press enter after I finish dictating my reasoning. This makes the tutor think I am often feeling 50% confident when I could actually be very confident or very unsure.

It would be nice to have a flow that made it harder to forget to set the confidence slider. An easy implementation would be adding a new setting "Start confidence unset", defaulted off so existing users are not affected.