Group dashboard UI improvements

Here we are going to make UI improvements and fix edge cases.

  • Use user-avatar-link components for avatars
  • Make components lowercase like TablePagination
  • Add missing aria-hidden on i tags
  • Align caret icon with parent folder icon
  • No need to make an AJAX request when toggling a folder since we already have the subgroups data
Edited by Alfredo Sumaran