Default number of cpus for podman machine should match podman default

[benoitf]

Is your enhancement related to a problem? Please describe

Podman change the default with https://github.com/containers/common/pull/1659

probably need to do the same in Podman Desktop

Describe the solution you'd like

Instead of having a default of 2, should have half of the number of cpus

Describe alternatives you've considered

No response

Additional context

No response