Improve component style primitives

[rauanmayemir]

We currently have styles that are set like border(~width, ~radius, ~color) or margin4(~top, ~left, ~bottom, ~right). This convention proved to be inconvenient because:

1. This forces us to check which props are set. E.g if we only want to set borderWidth we'll have to mimic 'undefined' behavior for other props
2. It's not very discoverable. paddingHorizontal or paddingVertical is easier to understand than padding2(~h, ~v, ())
3. It's harder to compose. `BorderRadius is used for layout calculation, so it looked hacky when we try to pull its value from `Border.

We should split up all the things to be applied individually: paddingLeft(), paddingTop(), borderColor, borderWidth, etc.