refactor: Create uhk-header component (#354)

Create a header wrapper component that will contains the undo
notification component.

shared/src/components/uhk-header/uhk-header.html

@@ -0,0 +1,3 @@
+<div>
+    <ng-content></ng-content>
+</div>

shared/src/components/uhk-header/uhk-header.ts

@@ -0,0 +1,9 @@
+import { ChangeDetectionStrategy, Component } from '@angular/core';
+
+@Component({
+    selector: 'uhk-header',
+    templateUrl: './uhk-header.html',
+    changeDetection: ChangeDetectionStrategy.OnPush
+})
+export class UhkHeader {
+}