Page unresposive when there are a lot of analytic units

[rozetko]

Browser page hangs when a dashboard with 100+ analytic units is opened

Reasons for this:

• segments / status requests for each analytic units are sent separately
• segments / status requests are sent even for hidden analytic units
• infinite refresh loop when dashboard timerange contains now

Related issues:

• https://github.com/hastic/hastic-server/issues/662
• https://github.com/hastic/hastic-grafana-app/issues/368