Expose client constants

`DEFAULT_GRPC_CALL_TIMEOUT` could be potentially tuned by the user and
`DEFAULT_CHANNEL_OPTIONS` is important as documentation for the
defaults.

Signed-off-by: Leandro Lucarella <[email protected]>

Author: llucax

src/frequenz/client/microgrid/__init__.py

@@ -8,6 +8,8 @@
 
 
 from ._client import (
+    DEFAULT_CHANNEL_OPTIONS,
+    DEFAULT_GRPC_CALL_TIMEOUT,
     MicrogridApiClient,
     Validity,
 )
@@ -43,6 +45,8 @@
     "ApiClientError",
     "ClientNotConnected",
     "ComponentId",
+    "DEFAULT_CHANNEL_OPTIONS",
+    "DEFAULT_GRPC_CALL_TIMEOUT",
     "DataLoss",
     "DeliveryArea",
     "EnergyMarketCodeType",