Proper implementation for ViewGroup - Sidebar

ViewGroup group a bunch of Ensemble View together behind a navigational menu. This is a ViewGroup:
```
ViewGroup:
  BottomNavBar|Sidebar|Drawer:
    items:
      - label: Home
        icon: home
        page: Home
      - label: Profile
        icon: person
        page: Profile
        selected: true
```
For this ticket, please implement only the Sidebar