Add comparison page

[justinanderson]

There's enough to the detail page and comparison menu to implement the comparison page now.

Rough Figma mockups:

• scrolled to top
• scrolled down

Make sure the comparison route includes comparison ids in its URL, e.g. /explore/small-business-support/comparison/405031120+406021140+401011001+404031105, so users can share links to a comparison.

Make the existing "View Comparison" button go to that route using the comparison ids in comparisonList.

Max width of each column should be 290px. Should probably have some min width as well, though what would be best will take some experimenting.