Rework the left minimap

[monvoisinf]

The minimap is the navigation menu on the left. In order to make navigation easier and improve documents visibility :

• enable an horizontally manual resizing
• add a functionality to collapse and expand folders and subfolders. Per default, have all folders collapsed
• enable to hide the minimap
• fix the issue that appears when cliking on a document on the bottom of the minimap, it reloads the minimap from the top and after a few seconds it scrolls down to the bottom
• remove the left padding :

  left-column li {
  padding-left: 0;
  display: block;