update the dashboard examples

[bassjobsen]

Please notice that many fixes are required for the issue already described at #17756.

There is also an issue for the sidebar with position: fixed in a flexbox item having now width, see also /* see http://stackoverflow.com/questions/34344623/fixed-position-element-inheriting-width-of-flex-item */
Solved for by:

width: calc(100% * (3/12));
@media (min-width: 768px) {
  .nav-sidebar {
    width: calc(100% * (2/12)); 
  }
}  

Code only tested on FF and Chrome

[bassjobsen]

close in favor of #18709

[bassjobsen]

see: #17816