Relevant recent changes

• set up the "Planning Overlays" tab in the UI (#44)
• loaded planning overlay data into the database (#49)
  • presently only dev_index is available
• added dev_index to the feature data embedded in the parcel map (#60)

Your mission

Get the map colored based on dev_index when you're on the "planning overlays" tab and have the "development suitability" toggle enabled

• See the "sale price" tab for an example of the map being colored based on a min/max number range, use the same color scale
• The min/max for dev_index will always be 1-100, you can hard-code this

Bonus points

• visually and functionally disable the "preservation" toggle, since it's data is not available yet but we want to keep the placeholder
• ready the code to support rendering both dev_index and pres_index to the map
  • both are scaled 1-100
  • when both are checked at the same time, add values together so the new scale is 2-200
  • whatever the scale, map its min/max to the same range of colors