Rename "container" to "image"

- Updated `wwctl upgrade` to handle updates
- Maintained `.Container` and `.ContainerName` in tstruct
- Added `ContainerName()` methods to node and profile objects
- Added `--container`, `-C` aliases to wwctl commands (`<node|profile> <add|set>`)
- Added `wwctl container` alias
- Added support for `container_exit.sh` if `image_exit.sh` is not found

Signed-off-by: Jonathon Anderson <janderson@ciq.com>

internal/app/wwctl/image/kernels/root.go

@@ -0,0 +1,24 @@
+package kernels
+
+import (
+	"github.com/spf13/cobra"
+
+	"github.com/warewulf/warewulf/internal/app/wwctl/completions"
+)
+
+var (
+	baseCmd = &cobra.Command{
+		DisableFlagsInUseLine: true,
+		Use:                   "kernels [OPTIONS]",
+		Short:                 "List available image kernels",
+		Long:                  "This command lists the kernels that are available in the imported images.",
+		RunE:                  CobraRunE,
+		Aliases:               []string{"kernel"},
+		ValidArgsFunction:     completions.Images,
+	}
+)
+
+// GetRootCommand returns the root cobra.Command for the application.
+func GetCommand() *cobra.Command {
+	return baseCmd
+}