TreeView (#725)

* feat(tree-view): add TreeView

* fix(tree-view): select initial active node, correct typedefs

* docs(tree-view): update examples

* chore(tree-view): add test for types

* docs(tree-view): rename example

* docs(tree-view): improve docs

* docs(tree-view): refine examples

* docs: fix invalid syntax

* chore: rebuild component index/api

* docs(layout): increase height of sidenav menu [ci skip]

src/index.js

@@ -126,6 +126,7 @@ export { ToggleSmall, ToggleSmallSkeleton } from "./ToggleSmall";
 export { Tooltip, TooltipFooter } from "./Tooltip";
 export { TooltipDefinition } from "./TooltipDefinition";
 export { TooltipIcon } from "./TooltipIcon";
+export { TreeView } from "./TreeView";
 export { Truncate } from "./Truncate";
 export {
   Header,