feat(path): Implement path component

Paths are horizontal process flows composed of a series of "stages". Like tabs, paths let users focus in on specific content at each stage whilst still keeping all the other stages in view.

This is needed for gitlab#213905 (closed) and was added to the design system via gitlab-design#1080 (closed)

Desktop	Mobile
Screen_Recording_2020-04-21_at_17.28.42	Screen_Recording_2020-04-24_at_14.11.53

Future iterations