Version 0.0.2: Update Example App with an Example Building

[ToluAta]

The example app is lacking examples.

The task would be to put in a button with the Label Create a Building in main.dart.
On press a new view would be opened with a form to fill in the needed fields with an expansion panel below it.
The expansion panel should show all of the buildings fields and their current values.
On open without a set building the expaned panel should reflect that (empty fields or text that states as much).

This issue is part of #4