Make week view all day header auto-adjust height to incidences and enable manual change of this view's height

This MR improves the all/multi day incidence view in the week view in two key ways:

1. The header automatically sets its height according to the number of lines of incidences
2. The user can now manually set the height of this same view by dragging

simplescreenrecorder-2021-10-24_00.33.48

This addresses #32 (closed)