Location field improvements

[evansiroky]

This PR has the following improvements:

• Adds a result type to the onLocationSelected callback (potentially resolves location field: more data returned from geocoder #13)
• Improve styling by (potentially resolves location field: styling improvements #12)
  • converting some plain jsx/html to styled components
  • adding a className to the root element to allow for styled-component styling
  • adding a story demonstrating how the LocationField component can be used as a styled component
• Allow customization of all the icons (potentially resolves location field: override icons (possibly using Slots pattern) #14)

This PR is built on top of #28

[binh-dam-ibigroup]

Are these "suggested" icon ids? In that case it should state so.

[binh-dam-ibigroup]

Are these "suggested" icon ids? In that case it should state so.

[fpurcell]

Looks good. I see the different icons for stops / stations / etc...

(Thinking that in a future update, we can add TriMet designer approved icons for these, and add them to the icons component, etc... But this should help AltSource now. Good job, Evan)