* portal
When there are too many items in the top menu, the menu is broken into
multiple lines (especially on medium screen resolution). This commit
implements a system like in the enterprise backend: the extra items are
placed in a "+" dropdown menu at the end of the top menu.
Also, review the direction used to open dropdown menus. The default is
now left-to-right (while it was right-to-left before) and JS has been
added to determine the safe direction:
- If last item: to the left instead
- If would overflow the window: to the other direction instead