Fixes #19377 - available_flavors for OpenStack

fixes GET /api/v2/compute_resources/:id/available_flavors resulting in
"Not implemented for OpenStack".

Fixes #19236 - handle situation when host is destroyed oVirt

The issue was introduced in 4269abbd, where we replaced the
`OVIRT::OvirtException` error by `ActiveRecord::RecordNotFound` in
`find_vm_by_uuid method`, but we haven't updated the corresponding...

Fixes #12272 - Support multiple certificates in ovirt resource

fixes #18064 - import host from compute resource

fixes #18815 - VMware vSphere Disk Mode support

fixes #18373 - vmware: do not pass automatic firmware to vm

Fixes #14716 - Added option to transform thin template to thick

Unfortunately, it's a single setting for all disks - you can't choose
which disks (inherited from templat) will be thin and which not.

For new disks, the logic remains the same - "thin" flag would be used.

fixes #18366 - vmware: delete vm only if created with errors

fixes #18216 - volume size editable for existing VMs one

fixes #13618 - cache expensive vmware api calls