Replace all instances of wwlog.Printf

wwlog provides named loggers for each level, which requires
less code and is clearer than wwlog.Printf. The code has
included a mix of both, but this commit consolidates existing
code on the per-level functions.

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

internal/pkg/node/datastructure.go

@@ -166,7 +166,7 @@ const NoValue = "--"
 func init() {
 	// Check that nodes.conf is found
 	if !util.IsFile(ConfigFile) {
-		wwlog.Printf(wwlog.WARN, "Missing node configuration file\n")
+		wwlog.Warn("Missing node configuration file\n")
 		// just return silently, as init is also called for bash_completion
 		return
 	}