Each day is now a component with a focus method.
The magic number: scrollMarginTop: '145px
Is the height of both headers & should be accessible in
script/template; but isn't.

The state is now in the handler

This version does not rely on internal state anymore.

The first working endless scroll.
But update of visible is broken now.

Leukeju's initial nav bar sketch is superseded.

Seems way more reliable than keeping scroll position (as was done
previously; inspired by the vue static site generator vuepress)

-> no more docsByDay state in component

fetchMore operates on the raw query result
query update fn is then called on the combined result
this result is then propagated through the page

Was loading while scrolling before!

This is the foundation of continuous loading (fetchMore).

It's important to keep the date out of computed gqlQueryArgs to not resend query.