On counciler pages, differentiate between types of sponsorships

[fgregg]

We probably want to make a special call out for legislation that a councillor is the primary sponsor for.

[cathydeng]

related to #109

right now, we only show primary sponsorships on person detail pages, which resolves this issue. however, it doesn't match with the content in the search view it links to, which is all sponsorships.

perhaps we should list all sponsorships to stay consistent with the search view, but have diff listing styles (less visually prominent, less info for non-primary sponsorships)