app/vmctl: disallow insecure https connections to vm-native-dst-addr and vm-native-src-addr by default

It is better from security PoV to disallow insecure https connections
to vm-native-dst-addr and vm-native-src-addr . This also maintains backwards compatibility
with vmctl before the commit 828aca82e9

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/5595
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/5606

app/vmctl/flags.go

@@ -471,12 +471,12 @@ var (
 		&cli.BoolFlag{
 			Name:  vmNativeSrcInsecureSkipVerify,
 			Usage: "Whether to skip TLS certificate verification when connecting to the source address",
-			Value: true,
+			Value: false,
 		},
 		&cli.BoolFlag{
 			Name:  vmNativeDstInsecureSkipVerify,
 			Usage: "Whether to skip TLS certificate verification when connecting to the destination address",
-			Value: true,
+			Value: false,
 		},
 	}
 )

app/vmctl/main.go

@@ -223,7 +223,9 @@ func main() {
 					}
 					srcHTTPClient := &http.Client{Transport: &http.Transport{
 						DisableKeepAlives: disableKeepAlive,
-						TLSClientConfig:   &tls.Config{InsecureSkipVerify: srcInsecureSkipVerify},
+						TLSClientConfig: &tls.Config{
+							InsecureSkipVerify: srcInsecureSkipVerify,
+						},
 					}}
 
 					dstAddr := strings.Trim(c.String(vmNativeDstAddr), "/")
@@ -238,7 +240,9 @@ func main() {
 					}
 					dstHTTPClient := &http.Client{Transport: &http.Transport{
 						DisableKeepAlives: disableKeepAlive,
-						TLSClientConfig:   &tls.Config{InsecureSkipVerify: dstInsecureSkipVerify},
+						TLSClientConfig: &tls.Config{
+							InsecureSkipVerify: dstInsecureSkipVerify,
+						},
 					}}
 
 					p := vmNativeProcessor{