Dashboards: Remove margins as it complicates the grid

Instead putting margins in the placeholder elements,
put appropriate margins within the children of .sorting element.
Dashboards: Make the border of placeholders looks a bit 'softer'
Dashboards: Add missing/incorrect conditions key
Merge branch '2.2-dashboard-polish' into 2.2

* 2.2-dashboard-polish:
  Dashboards: Add missing/incorrect conditions key
  Dashboards: Make the border of placeholders looks a bit 'softer'
  Dashboards: Remove margins as it complicates the grid