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/pkg/oci/defaults.go

@@ -6,7 +6,7 @@ import (
 	warewulfconf "github.com/warewulf/warewulf/internal/pkg/config"
 )
 
-var defaultCachePath = filepath.Join(warewulfconf.Get().Paths.Datadir, "/container-cache/oci/")
+var defaultCachePath = filepath.Join(warewulfconf.Get().Paths.Datadir, "/image-cache/oci/")
 
 const (
 	blobPrefix   = "blobs"