add point dilatation on hover (#841)

* enable centroid

* introduce new sizing

* scale point size based off hovered category

* add styling

* fix margins

* disable centroid labels

* remove unused code and add detail to comment

* remove cell dilation on selection toggle

* move hover to name label

* hover on value except for checkbox

* add border radius to value

client/src/components/categorical/categorical.css

@@ -0,0 +1,3 @@
+:local(.value):hover {
+  background: rgba(167, 182, 194, 0.3);
+}