fix: support placement groups

Change-Id: I8b3dfef59dccdc29d1f584656edd1f3a88cd5711
feature: support provisioned IOPS

Change-Id: I4c67b093172bdbe1b854eebaa6e7e113c0b2ef15
Merge pull request #360 from joshbronson/development_6

provisioned IOPs and placement groups for Ironfan