Add the availability to display separately the hosts in maintenance.

Two ways:

• New cell with all the hosts in maitenance
  • It can be more specific and display the information
    • if with data colection
    • if filtered by tags
• In the same cell of available/not avilable/unknown
  • 5 available 3 of wich in maintenance
  • 5 available (3 in maitenance - 2 with data colection - 1 filtered by tags)