Allow multi-org hypervisors

Hypervisor consumers should now be unique per org, not completely
unique.  Consumer now has a HypervisorId (one-to-one) which
enforces a unique constraint on hypervisor id per org.

All host and guest consumer lookups are limited to the requestors
org

Added /owners/{key}/hypervisors api
Allow owners to look up their hypervisors

Can specify create_missing=false on hypervisorCheckIn
Query parameter 'create_missing' allows hypervisor checkin
to be used to only update existing systems without creating
new hypervisor consumers
Merge pull request #520 from candlepin/ckozak/multiorg_hypervisors

ckozak/multiorg hypervisors