Set default min-height to every cards

[mturoci]

We use Flexbox for laying out the cards. The problem is it uses ratios by default. In case app dev wants to allow vertical scrolling, the cards still shrink and try to occupy viewport only. The solution to this is setting explicit heights to every row in order to enforce vertical scrollbars. This hurts DX a bit.

I propose setting reasonable defaults for min-height (and maybe also for min-width if makes sense) in order to simplify this usecase a bit.

Let's use this issue for discussion - @lo5 @geomodular.