Allow to customize icon for configurable actions

[jrmi]

Some actions like "rotation" can be configured (here we indicate the angle). Problem: for several different configurations of the same action, the icon is the same in the action menu (of selected items).

• Solution 1: we keep this, because by passing the mouse over the icons, we have the configuration information (for example for "rotation", the angle is indicated).
• Solution 2: in the icon's svg, we 'automatically' add the configuration information. For example for "rotation", in the svg image we could write the angle, and in a color other than gray.