Convert config to *bool

Supports leaving booleans unspecified in YAML.

Boolean methods allow the templates to continue using previous names for
boolean values.

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

internal/pkg/configure/nfs.go

@@ -17,8 +17,8 @@ func NFS() error {
 
 	controller := warewulfconf.Get()
 
-	if controller.NFS.Enabled {
-		if controller.Warewulf.EnableHostOverlay {
+	if controller.NFS.Enabled() {
+		if controller.Warewulf.EnableHostOverlay() {
 			err := overlay.BuildHostOverlay()
 			if err != nil {
 				wwlog.Warn("host overlay could not be built: %s", err)