added wwctl clean to remove cache/dead overlays

Signed-off-by: Christian Goll <cgoll@suse.com>

internal/app/wwctl/clean/main.go

@@ -0,0 +1,13 @@
+package clean
+
+import (
+	"github.com/warewulf/warewulf/internal/pkg/api/clean"
+
+	"github.com/spf13/cobra"
+)
+
+func CobraRunE(vars *variables) func(cmd *cobra.Command, args []string) (err error) {
+	return func(cmd *cobra.Command, args []string) (err error) {
+		return clean.Clean()
+	}
+}