Refactor buttons

[seagyn]

The buttons need to be refactored to be easier to use and conform to the design system. There isn't a need to make them dynamic but we do need to be able to override styles from the consumer (const NewButton = styled(Button)).

https://www.figma.com/file/bUBZY5aVyXYdedy2wCtDxr/Oxygen-Core?node-id=0%3A844

This might require the creation of a more elaborate and descriptive naming convention:

Primary, Secondary, Outline, Text

with props like noShadow, icon, disabled etc.

[chrysillala]

hi @seagyn , let me help you on this issue

[jenniferharmon]

hi @seagyn I have created a PR (#74) with some refactoring and additional button features (hover and active states, icons and icon/loader positioning). I hope it makes it easy to create buttons that conform to the style guide and also to customize styles.