Consolidate the default cluster name into as single definition

To ensure all reference of the default cluster name are the same.
Not having to check for typos will make it easier to maintain.

main.go

@@ -12,6 +12,7 @@ import (
 
 // defaultK3sImage specifies the default image being used for server and workers
 const defaultK3sImage = "docker.io/rancher/k3s"
+const defaultK3sClusterName string = "k3s-default"
 
 // main represents the CLI application
 func main() {
@@ -52,7 +53,7 @@ func main() {
 			Flags: []cli.Flag{
 				cli.StringFlag{
 					Name:  "name, n",
-					Value: "k3s-default",
+					Value: defaultK3sClusterName,
 					Usage: "Set a name for the cluster",
 				},
 				cli.StringFlag{
@@ -107,7 +108,7 @@ func main() {
 			Flags: []cli.Flag{
 				cli.StringFlag{
 					Name:  "name, n",
-					Value: "k3s-default",
+					Value: defaultK3sClusterName,
 					Usage: "name of the cluster",
 				},
 				cli.BoolFlag{
@@ -124,7 +125,7 @@ func main() {
 			Flags: []cli.Flag{
 				cli.StringFlag{
 					Name:  "name, n",
-					Value: "k3s-default",
+					Value: defaultK3sClusterName,
 					Usage: "Name of the cluster",
 				},
 				cli.BoolFlag{
@@ -141,7 +142,7 @@ func main() {
 			Flags: []cli.Flag{
 				cli.StringFlag{
 					Name:  "name, n",
-					Value: "k3s-default",
+					Value: defaultK3sClusterName,
 					Usage: "Name of the cluster",
 				},
 				cli.BoolFlag{
@@ -171,7 +172,7 @@ func main() {
 			Flags: []cli.Flag{
 				cli.StringFlag{
 					Name:  "name, n",
-					Value: "k3s-default",
+					Value: defaultK3sClusterName,
 					Usage: "Name of the cluster",
 				},
 				cli.BoolFlag{