MVP for Podman Machine with AppleHV

this pr is the first pass at enabling podman machine to use the apple hypervisor. there are still several TODO
areas like host networking.  once the decision is handled on what host networking should look like, these TODOs
should be fairly quick to resolve.  they also will impact the remove methods.

you must also have vfkit (https://github.com/crc-org/vfkit)

Signed-off-by: Brent Baude <bbaude@redhat.com>

[NO NEW TESTS NEEDED]

Signed-off-by: Brent Baude <bbaude@redhat.com>

cmd/podman/machine/platform.go

@@ -1,5 +1,4 @@
-//go:build (amd64 && !windows) || (arm64 && !windows)
-// +build amd64,!windows arm64,!windows
+//go:build (amd64 && !windows && amd64 && !darwin) || (arm64 && !windows && arm64 && !darwin) || (amd64 && darwin)
 
 package machine
 

cmd/podman/machine/platform_darwin.go

@@ -0,0 +1,36 @@
+//go:build darwin && arm64
+
+package machine
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/containers/common/pkg/config"
+	"github.com/containers/podman/v4/pkg/machine"
+	"github.com/containers/podman/v4/pkg/machine/qemu"
+	"github.com/sirupsen/logrus"
+)
+
+func GetSystemProvider() (machine.VirtProvider, error) {
+	cfg, err := config.Default()
+	if err != nil {
+		return nil, err
+	}
+	provider := cfg.Machine.Provider
+	if providerOverride, found := os.LookupEnv("CONTAINERS_MACHINE_PROVIDER"); found {
+		provider = providerOverride
+	}
+	resolvedVMType, err := machine.ParseVMType(provider, machine.QemuVirt)
+	if err != nil {
+		return nil, err
+	}
+
+	logrus.Debugf("Using Podman machine with `%s` virtualization provider", resolvedVMType.String())
+	switch resolvedVMType {
+	case machine.QemuVirt:
+		return qemu.GetVirtualizationProvider(), nil
+	default:
+		return nil, fmt.Errorf("unsupported virtualization provider: `%s`", resolvedVMType.String())
+	}
+}