A VM created without a cpu argument gets Proxmox's API default, kvm64: no
AES-NI and no AVX. MongoDB 5.0 and later exit with "Illegal instruction" on
it, which is how a Graylog provisioned through netOrk failed (netork#494).
Every VM built by hand in the same cluster uses host or x86-64-v2-AES; only
the ones this driver created were left on kvm64.
create_vm_from_cloud_init now always passes cpu=, defaulting to x86-64-v2-AES
as the Proxmox GUI does since PVE 8, and takes cpu_type for a different one.
get_vm_cpu_types() lists x86-64-v2-AES (default), x86-64-v3 and host. The
named models carry the cpuinfo flags they add over qemu64, following
Proxmox's own definitions (CPUConfig.pm), and are available when the node's
CPU has all of them, read from /nodes/{node}/status. host lists the node's
own flags, so on a CPU without AVX it does not pretend to offer any.
A model asked for by name is checked against the node before a VMID is
allocated: one the CPU cannot run would only fail at VM start, after the disk
import, leaving a half-built VM behind. The default is not checked, so a
plain create costs no extra API call. VMCpuTypeDict is imported for type
checking only, so this works with an older napalm_device_types.