Implement groups view in sidebar using Vue

[UnniKohonen]

Description of the enhancement

Adding a Vue component for group view in the sidebar.

What new functionalities would the enhancement make possible?

• 1 Implement basic functionality of groups view using Vue #1710
  • 1.1 Loading and building correct tree structure when group hierarchy is not expanded (on vocab home)
  • 1.2 Loading and building correct tree structure when group hierarchy is expanded (on group page)
  • 1.3 Loading new groups/concepts into group hierarchy
  • 1.4 Displaying group hierarchy in UI
• 2 Partial page load
• 3 CSS & layout
  • 3.1 Correct sidebar sizing
    • 3.1.1 Correct height and width on load
    • 3.1.2 Correct width on window resize
  • 3.2 Icons and lines
  • 3.3 Highlighting selected group/concept
  • 3.4 Colors, text weight, etc.
  • 3.5 Loading spinners
• 4 Configuration options
  • 4.1 showNotation (showing notation codes in group hierarchy)
• 5 Sorting groups/concepts by label according to localization
• 6 Cypress tests
• 7 Showing concept members if the group has other groups as members (see Hierarchy view does not display concepts when concept groups are on the same level #620)