Assign ownership to many libs files (#6928)

Assign ownership to many of the remaining libs/common files.

Criteria for ownership:
* Files used by a single team, is now owned by that team.
* Files related to a domain owned by a team is now owned by that team.
* Where ownership is unclear the "lowest level" service takes ownership.

libs/common/src/vault/models/domain/tree-node.ts

@@ -0,0 +1,21 @@
+export class TreeNode<T extends ITreeNodeObject> {
+  node: T;
+  parent: TreeNode<T>;
+  children: TreeNode<T>[] = [];
+
+  constructor(node: T, parent: TreeNode<T>, name?: string, id?: string) {
+    this.parent = parent;
+    this.node = node;
+    if (name) {
+      this.node.name = name;
+    }
+    if (id) {
+      this.node.id = id;
+    }
+  }
+}
+
+export interface ITreeNodeObject {
+  id: string;
+  name: string;
+}