refactor: build site with rollup, share functions between scraper and site

[lazd]

Things I'm doing here:

• Use rollup to bundle site
• Split out site pages into separate modules
• Share dependencies between frontend and scraper
• Refactor/regroup and move around many library functions
• Figure out why editing index.html doesn't copy it
• Live reload
• Test deployment

Things we should still do after this PR:

• A little more refactoring in site modules (cache querySelector calls)
• Make the page refresh when data updated
• Bundle mapboxgl, PapaParse, and handsontable?
• Update README and getting started docs

Things I'm not doing here:

• Using proper routing on the site
• Making the site not suck

[lazd]

@ryanblock @qgolsteyn can you take a look at this and just merge it if it's OK? We can finish up the rest of the todos later. Folks are contributing things like #188, #203, and @NateBaldwinDesign is working on the map, and I want to get this refactor out of their way.

Thanks!

[ryanblock]

cc @brianleroux

[camjc]

Some potentially off-topic comments (just because moving lots of files so reading bits I hadn't before). Feel free to accept or reject and get this sucker in.

[camjc]

LGTM