Redaction with toolbar and fixed toolpanel

redaction: move "Dépêche Urgent" to "Détails", correctly uses flexbo for "Discussion", remove h1 style for the toolpanel

redaction: fix CSS rules for large screens (don't set min-width and adjust toolbar position when panel is not shown)

redaction: on mobile, clear the box-shadow of toolpanel and keep border and 8px margin for toolbar-toc

add variables for inactive tab and "sombre" colors.
use opacity 100% for not-active-underline background image.

news/_toolbar: on click of summary popup, close it back and let continue action (like follow link anchor)