Support html5 elements

[omid-ebrahimi]

I think this lib should support html5 elements (ex: section, article instead of div).
1- We can add an option to Box to specify element type.
2- We can also define new components (ex: FlexArticle, FlexSection).
We can also implement both solutions.

[jxnblk]

You can use the as prop to change the underlying HTTML element (e.g. <Box as='header' />) see https://www.styled-components.com/docs/api#as-polymorphic-prop