RFC: replace the current Contour Icon in the upper corner through a proper icon

[Fania Bremmer]

** Proposed Change **
Replace the current Contour Icon in the upper corner through a proper 
icon that indicates "Homescreen", "Current Activity"...

** Reason For Change **
Not one user pressed this icon himself. After seeing what it means, 
every user pressed it to get back to the current activity and it felt 
very intuitiv and in the flow.
So, we need a better icon and maybe a new positioning on the screen, the 
feature itself is phantastic and need.

** Implementation Details **
- create a new icon
- test where it fits best on the screen, do user testing