Revise Spawn and Minion to use simpler rebalance workflow
Remove chore framework and related tests. Revise imports.
Minion should kill only rsyncs it initiated
Rebalance method cleanups
Tasks store rebalance sources/targets. Stopping a rebalancing task will pause the rebalance until the next kick; killing it will terminate the rebalance permanently.
Revise minion stop/kill behavior when replication is for rebalancing
Prevent NPE in host scoring
Add optional copy bandwidth limit (useful for minion testing)
Implement a Rebalance_Pause exit code, to make sure spawn can distinguish between prematurely-terminated rsyncs and ones that actually finished.
Clear the target for stopped migrating task.
Prevent NPE in getHostState