rclone config redacted: implement support mechanism for showing redacted config

This introduces a new fs.Option flag, Sensitive and uses this along
with IsPassword to redact the info in the config file for support
purposes.

It adds this flag into backends where appropriate. It was necessary to
add oauthutil.SharedOptions to some backends as they were missing
them.

Fixes #5209

cmd/config/config.go

@@ -26,6 +26,7 @@ func init() {
 	configCommand.AddCommand(configTouchCommand)
 	configCommand.AddCommand(configPathsCommand)
 	configCommand.AddCommand(configShowCommand)
+	configCommand.AddCommand(configRedactedCommand)
 	configCommand.AddCommand(configDumpCommand)
 	configCommand.AddCommand(configProvidersCommand)
 	configCommand.AddCommand(configCreateCommand)
@@ -118,6 +119,35 @@ var configShowCommand = &cobra.Command{
 	},
 }
 
+var configRedactedCommand = &cobra.Command{
+	Use:   "redacted [<remote>]",
+	Short: `Print redacted (decrypted) config file, or the redacted config for a single remote.`,
+	Long: `This prints a redacted copy of the config file, either the
+whole config file or for a given remote.
+
+The config file will be redacted by replacing all passwords and other
+sensitive info with XXX.
+
+This makes the config file suitable for posting online for support.
+
+It should be double checked before posting as the redaction may not be perfect.
+
+`,
+	Annotations: map[string]string{
+		"versionIntroduced": "v1.64",
+	},
+	Run: func(command *cobra.Command, args []string) {
+		cmd.CheckArgs(0, 1, command, args)
+		if len(args) == 0 {
+			config.ShowRedactedConfig()
+		} else {
+			name := strings.TrimRight(args[0], ":")
+			config.ShowRedactedRemote(name)
+		}
+		fmt.Println("### Double check the config for sensitive info before posting publicly")
+	},
+}
+
 var configDumpCommand = &cobra.Command{
 	Use:   "dump",
 	Short: `Dump the config file as JSON.`,