UI Updates for Storage

- Added style for app-header (this includes the global action button) when clicked it needs to display a modal.
- Added the styles for toolbar, including folder navigation and the toolbar actions icons.
- Added some styles for responsive views.

@ghislaineguerin yes `btn-lg` is still being used all over the app. If you want it to be 40px in the storage component then wrap it in the storage component class, don't pollute the global namespace:
```
.storage-component {
  .btn-lg { ... }
  .btn-rv-help { ... }
}
```