feat: Margins not only for Box

[tassoevan]

Expand the usage of Margins to accept any kind of React element that accepts a className prop.

N.B.: you can't override Margins elements by composing them, i.e., this:

<Margins all='x16'>
  <Margins all='x8'>
    <div />
  </Margins>
</Margins>

will not have a defined behavior.