UI: Small alignment changes on the homescreen

- changed the scroll bar to the wider version
- removed the padding around the whole screen
- added a bit of padding to the menu-buttons

The idea is to make it consistent with kano-profile
and the new redesign of kano-apps.

Related to: https://github.com/KanoComputing/peldins/issues/1258
UI: Home screen typography

Adjusting the labels alignment slightly.
Merge pull request #170 from KanoComputing/homescreen-refactor

UI: Small alignment changes on the homescreen