Unexport secret commands

This patch deprecates exported secret commands and moves the implementation
details to an unexported function.

Commands that are affected include:

- secrets.NewSecretCommand

Signed-off-by: Alano Terblanche <18033717+Benehiko@users.noreply.github.com>

cli/command/commands/commands.go

@@ -75,6 +75,7 @@ func AddCommands(cmd *cobra.Command, dockerCli command.Cli) {
 		//nolint:staticcheck // TODO: Remove when migration to cli/internal/commands.Register is complete. (see #6283)
 		config.NewConfigCommand(dockerCli),
 		node.NewNodeCommand(dockerCli),
+		//nolint:staticcheck // TODO: Remove when migration to cli/internal/commands.Register is complete. (see #6283)
 		secret.NewSecretCommand(dockerCli),
 		service.NewServiceCommand(dockerCli),
 		stack.NewStackCommand(dockerCli),