Added dropdown links to download API calls from the API page.

[davphan]

Resolves #3237

Non-technical users were having trouble downloading API data for external usage. Dropdown buttons were added to the three major API calls (attributes with labels, score streets, and score neighborhoods) with one-click download options for CSV, Shapefile, and GeoJSON format.

GeoJSON format links to the JSON in browser rather than downloading a JSON file.

Before/After screenshots (if applicable)

Before:

After:

Testing instructions

1. Go the API page by clicking the "API" tab from the navbar.
2. Under each of the three main API call sections, click on the dropdown button and try clicking each of the three download options (CSV, Shapefile, GeoJSON).

Things to check before submitting the PR

• I've written a descriptive PR title.
• I've added/updated comments for large or confusing blocks of code.
• I've included before/after screenshots above.

[misaugstad]

The functionality seems great! Most of these edits have to do with rewriting some of the text and such on the API page to accommodate the changes you've made!

1. Let's have separate widgets for /attributes and /attributesWithLabels

2. The lat/lng bounds should be listed as "Optional" instead of "Required". This just means removing the entire "Required" category and moving the lat/lngs part inside the "Optional" section.

3. In places where you see this sentence

   If you need data for the entire city, you can use the parameters below

   Replace it with

   If you need data for the entire city, you can use the download button above or you can simply exclude the lat/lng parameters.

4. There are more changes to make given that the params are now optional... Just use your best judgement and try to get the page to work with the now optional parameters and download widgets!

5. The download widgets are kinda floating way higher than the titles that are in the same row. Can you add some margin to the buttons or something to move them more in line with the text? It just looks kinda clunky rn

6. Let's also open the URLs in the widgets in a new tab!

[davphan]

@misaugstad Ready for another review!