Replace default export with named exports (#1998)

## Launch Checklist

See title,
Also removed some "_" from some file names.
This is a pure refactoring, no logic changes.


 - [x] Briefly describe the changes in this PR.

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

src/components/IconLayer.tsx

@@ -13,7 +13,7 @@ type IconLayerProps = {
   className?: string
 };
 
-const IconLayer: React.FC<IconLayerProps> = (props) => {
+export const IconLayer: React.FC<IconLayerProps> = (props) => {
   const iconProps = { style: props.style };
   switch(props.type) {
     case "fill-extrusion": return <IoMdCube {...iconProps} />;
@@ -29,5 +29,3 @@ const IconLayer: React.FC<IconLayerProps> = (props) => {
     default: return <MdPriorityHigh {...iconProps} />;
   }
 };
-
-export default IconLayer;