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]

tests/TreeView.test.svelte

@@ -0,0 +1,59 @@
+<script lang="ts">
+  import { TreeView } from "../types";
+  import type { TreeNodeId } from "../types/TreeView/TreeView";
+  import Analytics16 from "carbon-icons-svelte/lib/Analytics16";
+
+  let activeId: TreeNodeId = "";
+  let selectedIds = [];
+  let children = [
+    { id: 0, text: "AI / Machine learning", icon: Analytics16 },
+    {
+      id: 1,
+      text: "Analytics",
+      children: [
+        {
+          id: 2,
+          text: "IBM Analytics Engine",
+          children: [
+            { id: 3, text: "Apache Spark" },
+            { id: 4, text: "Hadoop" },
+          ],
+        },
+        { id: 5, text: "IBM Cloud SQL Query" },
+        { id: 6, text: "IBM Db2 Warehouse on Cloud" },
+      ],
+    },
+    {
+      id: 7,
+      text: "Blockchain",
+      children: [{ id: 8, text: "IBM Blockchain Platform" }],
+    },
+    {
+      id: 9,
+      text: "Databases",
+      children: [
+        { id: 10, text: "IBM Cloud Databases for Elasticsearch" },
+        { id: 11, text: "IBM Cloud Databases for Enterprise DB" },
+        { id: 12, text: "IBM Cloud Databases for MongoDB" },
+        { id: 13, text: "IBM Cloud Databases for PostgreSQL" },
+      ],
+    },
+    {
+      id: 14,
+      text: "Integration",
+      disabled: true,
+      children: [{ id: 15, text: "IBM API Connect", disabled: true }],
+    },
+  ];
+</script>
+
+<TreeView
+  size="compact"
+  labelText="Cloud Products"
+  children="{children}"
+  bind:activeId
+  bind:selectedIds
+  on:select="{({ detail }) => console.log('select', detail)}"
+  on:toggle="{({ detail }) => console.log('toggle', detail)}"
+  on:focus="{({ detail }) => console.log('focus', detail)}"
+/>