Feature request: Add Garbage Collection telemetry

[robacourt]

Currently we can't account for all the time spent processing the replication stream. One hypothesis is that Garbage Collection is slowing the processing down.

The Erlang In Anger book documents how to use erlang:system_monitor(self(), [{long_gc, 500}]). for this means.

The telemetry should break the time spent down by process type (As defined in Electric.Debug.Process)