wizardview: logic refinement for account creation and minor UI changes

1. Add spinner button and logic when waitting for account created to
prevent reclicking the buttons

2. Add back button when creating accounts in main view.

3. Fix the look up username bug

4. Change some buttons to blue styled

5. Change back button to back arrow

6. Add autofocus when entering certain page

Gitlab: #59
Change-Id: I3cada8c07a6605f091001db75a2913cde379c41b