Solve for event types where checking in involves selecting from a collection of subcategories

**Motivating case**: Emotion.

**Problem**: Lots of emotions will (and should) get registered. Current design path will enumerate all of them when user just wants to check in one.

**Simple solution**: User can select emotion from an alphabetical drop down. Only one checkin "card" presented for the entire event type (category) of "emotion"

**Simpler solution**: User just writes in their emotion as a comment. Hugely not preferable, but would work for the interim.

**Preferred behavior**: User can drill down through emotion categories or otherwise is somehow assisted to find the best emotion for how they are currently feeling, without cluttering the page.