Most daemons have a "go as fast as you can then sleep for 30 seconds"
strategy towards resource utilization; the object-updater and
object-auditor however have some "X_per_second" options that allow
operators much better control over how they spend their I/O budget.
This change extends that pattern into the account-replicator,
container-replicator, and container-sharder which have been known to peg
CPUs when they're not IO limited.
Partial-Bug: #1784753
Change-Id: Ib7f2497794fa2f384a1a6ab500b657c624426384
06cf5d298f