[WIP] Support for running placement of infrastructure vms from Automate State Machine

https://bugzilla.redhat.com/show_bug.cgi?id=1129748

This PR has code changes as well as the Automate DB changes for
the ManageIQ domain. The placment code has backward compatibility
support for earlier versions of CFME, where the placement logic is
called via UI_PROVISION_INFO requests. The default automate methods
provide the cluster and least utilized support for REDHAT and VMWare
respectively.
@tinaafitz @gmcculloug 
The placement class has attributes like vm/host/storage/storage_max_vms/storage_max_pct_used I am going to leave those around and delete the others