Add modal with contextual information and searches

[dboyer]

Modal should include:

• Text (below)
• Three default searches that lead to different cities with pre-set layers selected (Deb will select)
• Location search box

Modal will be skipped if the url includes a center=lat,lng query parameter.

The job of the modal is to set a center=lat,lng query parameter

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Intro paragraph:

Trees provide countless economic, social, and environmental benefits. Discover optimal tree planting locations based on environmental and demographic data. Using the sidebar on the left of the page, set the priorities that connect to your planting goals, choose the zip codes you would like to see, and view maps displaying possible planting areas.

Search links:

Search Box Text: Enter location to view maps

Los Angeles: Explore planting locations related to environmental justice

Philadelphia: Find planting locations where the most people live

Chicago: Discover planting locations with low housing vacancy rates

[dboyer]

@jwalgran I'm not seeing the prioritize plantings link when viewing a map in Firefox. I do see it in Chrome and Safari.