refactor: break up cli pkg into nice small chunks

cli/app/app.go

@@ -0,0 +1,32 @@
+package app
+
+import (
+	"github.com/urfave/cli/v2"
+)
+
+var AppCommand = &cli.Command{
+	Name:  "app",
+	Usage: "Manage your apps",
+	Description: `
+This command provides all the functionality you need to manage the lifecycle of
+your apps. From initial deployment to day-2 operations (e.g. backup/restore) to
+scaling apps up and spinning them down.
+`,
+	Subcommands: []*cli.Command{
+		appNewCommand,
+		appConfigCommand,
+		appDeployCommand,
+		appUndeployCommand,
+		appBackupCommand,
+		appRestoreCommand,
+		appRemoveCommand,
+		appCheckCommand,
+		appListCommand,
+		appPsCommand,
+		appLogsCommand,
+		appCpCommand,
+		appRunCommand,
+		appRollbackCommand,
+		appSecretCommand,
+	},
+}