Create hover effect from PMTiles source

[mizmay]

Putting this aside until I can debug what's going on.

1. Need a way to set promoteId to something unique, e.g. "name"

2. Set hoverstate:

               map.on('mousemove', 'states', (e) => {
                   if (e.features.length > 0) {
   
                       if (hoveredStateId) {
                           map.setFeatureState(
                               {source: 'states', id: hoveredStateId},
                               {hover: false}
                           );
                       }
                       hoveredStateId = e.features[0].properties.name;
                       map.setFeatureState(
                           {source: 'states', id: hoveredStateId},
                           {hover: true}
                       );
                   }
               });
   
               map.on('mouseleave', 'states', () => {
                   if (hoveredStateId) {
                       map.setFeatureState(
                           {source: 'states', id: hoveredStateId},
                           {hover: false}
                       );
                   }
               hoveredStateId = null;
               });

[mizmay]

Debugging using geojson source:

                            'states': {
                                type: "geojson",
                                data: "https://mizmay.github.io/WebMapStarterKit/states_swing_2020_coterminoususa.geojson",
                                promoteId: "name"
                            }