US dams example dashboard

[allisonhorst]

Deployed version is here: https://observablehq.observablehq.cloud/framework-example-us-dams/

Working version of a new example, with data on dam condition, location, hazard potential, etc. from the National Inventory of Dams.

Still to update:

• marginLeft on horizontal bar chart (top left of by-state.md) to adjust if the longest type "Fire Protection, Stock, Or Small Fish Pond" isn't in the top 10 (otherwise too much blank space)
• Overlapping container on by-state.md search bar (sometimes makes it unclickable)
• Zoom window change based on polygon bounding box on by-state page (fitBound, possibly)
• ~Fix resize issues (e.g. for summary text box)~
• ~Move search box to top of table (issue with being non-clickable)~
• ~Add color to the risk grid (hazard + condition counts, square bubble chart). Ideally this would help indicate "worst" scenario when condition = poor and hazardPotential = High, "best" scenario when condition = fair and hazardPotential = Low, and gray / unknown when either condition or hazardPotential are unknown. Not sure how to accomplish this.~ (only based on condition, maybe add different scheme later on)
• ~Stroke around capital text~
• ~Condition order in yearCompleted histogram~