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/api/node/list.go

@@ -74,7 +74,7 @@ func NodeList(nodeGet *wwapiv1.GetNodeList) (nodeList wwapiv1.NodeList, err erro
 		}
 	} else if nodeGet.Type == wwapiv1.GetNodeList_Long {
 		nodeList.Output = append(nodeList.Output,
-			fmt.Sprintf("%s:=:%s:=:%s:=:%s", "NODE NAME", "KERNEL VERSION", "CONTAINER", "OVERLAYS (S/R)"))
+			fmt.Sprintf("%s:=:%s:=:%s:=:%s", "NODE NAME", "KERNEL VERSION", "IMAGE", "OVERLAYS (S/R)"))
 		for _, n := range node.FilterNodeListByName(nodes, nodeGet.Nodes) {
 			kernelVersion := ""
 			if n.Kernel != nil {
@@ -83,7 +83,7 @@ func NodeList(nodeGet *wwapiv1.GetNodeList) (nodeList wwapiv1.NodeList, err erro
 			nodeList.Output = append(nodeList.Output,
 				fmt.Sprintf("%s:=:%s:=:%s:=:%s", n.Id(),
 					kernelVersion,
-					n.ContainerName,
+					n.ImageName,
 					strings.Join(n.SystemOverlay, ",")+"/"+strings.Join(n.RuntimeOverlay, ",")))
 		}
 	} else if nodeGet.Type == wwapiv1.GetNodeList_All {