Want provision protections if virtualization is not available.

[bahamat]

Sysinfo will set Bhyve Capable if bhyve VMs can be created, and VM Capable if KVM VMs can be created.

All modern x86_64 processors have virtualization capability, however they can be disabled in the machine settings (BIOS, hardware setup, or VM "nested" virt). This can lead to VMs being created that are unable to start, and have unhelpful errors (vm.exit_status = -134).

To assist users, if HVM capability flag for the chosen brand type is not true, then we should display a warning banner to the effect of processor virtualization being disabled, and disable the final create button, but leave the rest of the VM Create form as-is.

See #4 for an example of this issue.