Add more autoscale pool logging to daemons in verbose mode

Summary:
Ref T12331. This is intended to make T12331 easier to debug because I'm having difficulty reproducing the issue locally.

Autoscale pools now log, and don't update more than once per second.

Test Plan: Ran bin/phd debug task --pool 4, saw pool scaling logs.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T12331

Differential Revision: https://secure.phabricator.com/D17432