Add a scheduling_group_name filter to the overview dashboard

[amnonh]

This series make the metric related scheduling_group filtered with a default value.
This makes it clearer what are the real latencies and what are internal latencies
Fixes #1939

[mykaul]

Are there any other internal latency metrics we take into account that we should exclude as well?

[amnonh]

I addressed it with two approaches:

1. I excluded all the current internal scheduling group
2. the filter allows you to choose which scheduling group are take in to account.