Modularize status tracking for pools of components in the power distributing actor (#779)

The new design works as follows:

- reusable `ComponentPoolStatusTracker` that takes individual
`ComponentStatus` and generates `ComponentPoolStatus` objects.
- the individual `ComponentStatus` need to be generated by code specific
to the component category, because status is calculated differently for
different component categories. This code specific for a component
category has to be a class that implements the abstract
`ComponentStatusTracker` class.
- The `ComponentPoolStatusTracker` accepts implementations of
`ComponentStatusTracker`, like the `BatteryStatusTracker` (which looks
at the status of corresponding inverters also), and but is otherwise
generic.

This PR takes us part of the way towards getting the
PowerDistributingActor easily usable for other component types.

It also simplifies some implementations and replaces the use of
`MergeNamed` with `Merge` from the channels repo.

Author: shsms

benchmarks/power_distribution/power_distributor.py

@@ -16,7 +16,7 @@
 from frequenz.sdk import microgrid
 from frequenz.sdk.actor import ResamplerConfig
 from frequenz.sdk.actor.power_distributing import (
-    BatteryStatus,
+    ComponentPoolStatus,
     Error,
     OutOfBounds,
     PartialFailure,
@@ -112,7 +112,7 @@ async def run_test(  # pylint: disable=too-many-locals
     start = timeit.default_timer()
 
     power_request_channel = Broadcast[Request]("power-request")
-    battery_status_channel = Broadcast[BatteryStatus]("battery-status")
+    battery_status_channel = Broadcast[ComponentPoolStatus]("battery-status")
     power_result_channel = Broadcast[Result]("power-result")
     async with PowerDistributingActor(
         requests_receiver=power_request_channel.new_receiver(),

src/frequenz/sdk/actor/power_distributing/__init__.py

@@ -10,7 +10,7 @@
 PowerDistributingActor and send requests for charging or discharging power.
 """
 
-from ._battery_pool_status import BatteryStatus
+from ._component_status import ComponentPoolStatus
 from .power_distributing import PowerDistributingActor
 from .request import Request
 from .result import Error, OutOfBounds, PartialFailure, Result, Success
@@ -23,5 +23,5 @@
     "Success",
     "OutOfBounds",
     "PartialFailure",
-    "BatteryStatus",
+    "ComponentPoolStatus",
 ]