Connecting sidebar and map

[jfrankl]

Currently, the only way to see the connection between a district in the sidebar and the map is the color. On a project with ~20 districts, this will be fine for most users. For users who experience colorblindness, and maps with many more districts, this will not be enough. We should explore other ways to allow users to explore this connection.

1. Tooltip

When a user is looking at a district on the map, they want to know the name of the district. The user can right click on the map to show a special context menu that displays the district they are hovering and a shortcut to start editing that district.

2. Highlight selected district and/or on hover

When the user is looking at a district in their sidebar, they want to quickly figure out which district on the map it corresponds to. The active district (district being edited) should have a thick border to make it stand out from the rest. When the user hovers a district in the sidebar, that district should temporarily receive the same treatment. An overflow menu provides the option to "Zoom to district", further connecting the sidebar to the map.

3. Label

We could generate labels on the map that show the district number. I made a branch that gets this 80% of the way there, but it would need some more time to fully implement, and we'll want a way to toggle it on and off. https://github.com/PublicMapping/districtbuilder/tree/feature/jdf/map-district-number

[tgilcrest]

(Added numbers to refer to them)

I like 1 and 3 a lot. I'm wary of doing 2 on the main map interface because I think it could be challenging to to get the cartography right with basemaps and zooming. I think 2 could work better on a summary report where it's not interactive and would be more static (and depending on the medium of the report, 1 and 3 may not be possible.)