Feature Request: Maintenance indicator

[datawolk]

Is your feature request related to a problem? Please describe.
When one agent is put into maintenance, all of the client/site will turn green.
Because of this you cannot see if another agent has alerts.

Describe the solution you'd like
A solution would be to still color the client / site orange / red on alerts but possibly with a small indicator bullet that there is an agent in maintenance on this site / client.

Describe alternatives you've considered
Daily maintenance client/sites checking.
Provides a lot of overhead of work.

Additional context

Sample solution:
In this client, an agent with maintenance is active.
But another agent issues an Alert causing the site to turn orange.

[sebvonhelsinki]

The problem is the same one reported in #1221 , but with a different solution