It now feels like a premature optimization to make anything
that inherets from Page be wrapped in a grid layout.
Notice that a "Page" here is the thing we push on the card-stack, the
Page has the back icon and the header text.
This improves the TextButton to be more re-usable and have an arrow to
make it clear it actually is a button.
Added a sub-text as well.
This made it really easy to make an About page with some subpages or
external links.
Also increased the top-header from 40 to 50 'pixels'.