Show information about currently running queries

[SloNN]

When the database is loaded, it's important to understand exactly what it's doing. I suggest to start displaying information about currently executing queries

The data is located in the .sys/query_sessions system table.
Query:

select * from .sys/query_sessions limit 10

[SloNN]

I suggest to split this page on two parts. First part (table) with currently running queries and the Second one with Top queries

[antonkovalenko]

#1325 some improvements