Clear way to use one aggregator in multiple pools

[skipor]

Usually, even when using multiple instance pools, wanted to use one Aggregator for them.
Now, phout aggregator solving this problem in not clear way: aggregator config passed to all needed places, but underhood only aggregator created, but many Run routines started. And seems, that there are some bugs in this non clear implementation.

I propose add explicit mechanism to use one aggregator in multiple pools.
How I think it should be looking in config:

pools:
  - ...
    aggregator: 
      type: master
      # key: some_key # "default" by default, so should not be typed when only master created.
      config:
        type: phout
        ....
  - ...
    aggregator:
      - type: slave
       # key: some_key # "default" by default, so should not be typed when only master created.

Master and slaves use one global registry, where found each other config key.
Only master runs real aggregator background routine, and it's context should not be canceled until master and all slaves context cancel. Context values passed from master context.

Slave aggregator instance should just block until context cancel, or master subroutine finished