Add selection save & restore

[jrmi]

Just like the views, we could have groups of selected elements (for example for a card, the draw pile, the discard pile). Visually, after having created a group of selected elements (creation which could be done in the action menu, or in another place by clicking on an icon), we could see a horizontal list appear at the top (in the form of successions of rectangles) from each of the groups. Clicking on one of the rectangles allows you to select the elements of the corresponding group. We could also have keyboard shortcuts like for views. In addition, we could name these groups (eg: draw pile, etc.).