[feature] Add a clustering feature to geographic map

[totallynotvaishnav]

Implement a clustering feature to geographic map such that the multiple overlapping elements are grouped as one cluster. The cluster should:

• Expand when it’s hovered with the mouse
• Expand when the map zoom increases

This would involve:

• Creating a new utility function to identify the clusters. These clusters will be rendered on the map instead of individual nodes.
• Clusters are expanded on hover or zoom through echarts actions and events.