podman: add new cgroup mode split

When running under systemd there is no need to create yet another
cgroup for the container.

With conmon-delegated the current cgroup will be split in two sub
cgroups:

- supervisor
- container

The supervisor cgroup will hold conmon and the podman process, while
the container cgroup is used by the OCI runtime (using the cgroupfs
backend).

Closes: https://github.com/containers/libpod/issues/6400

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

utils/utils_windows.go

@@ -7,3 +7,15 @@ import "github.com/pkg/errors"
 func RunUnderSystemdScope(pid int, slice string, unitName string) error {
 	return errors.New("not implemented for windows")
 }
+
+func MoveUnderCgroupSubtree(subtree string) error {
+	return errors.New("not implemented for windows")
+}
+
+func GetOwnCgroup() (string, error) {
+	return "", errors.New("not implemented for windows")
+}
+
+func GetCgroupProcess(pid int) (string, error) {
+	return "", errors.New("not implemented for windows")
+}