Fix correct header rank and keyboard naviagtion

[tilen1976]

This offers a solutions for faults fault in header ranks and not possible to navigate Tabs with keyboard. Both important for accessibility and machine reading:

• A title for each workspace with correct header in order to place the workspace in the correct rank order (open for suggestions for title content)
• A solution to make dash core component Tabs accessible for keyboard navigation:
  • Use 'Keyboard' from 'dash extensions'
  • wrap tabs in focusable div with tabindex
  • add callback to handle keyboard navigation for Tabs

[Jorgen-5]

Looks good!