app: remove JSON based schema, and each App returns single namespace

Change-Id: I2ced82edd1251edc592f7ae0156d5ea3c81865c2
diff --git a/core/installer/app_manager.go b/core/installer/app_manager.go
index 4684e02..295c8ff 100644
--- a/core/installer/app_manager.go
+++ b/core/installer/app_manager.go
@@ -59,18 +59,13 @@
 	if err != nil {
 		return err
 	}
-	namespaces := make([]string, len(app.Namespaces()))
-	for i, n := range app.Namespaces() {
-		ns, err := ns.Generate(n)
-		if err != nil {
-			return err
-		}
-		namespaces[i] = ns + suffix
+	nms, err := ns.Generate(app.Namespace())
+	if err != nil {
+		return err
 	}
-	for _, n := range namespaces {
-		if err := m.nsCreator.Create(n); err != nil {
-			return err
-		}
+	nms = nms + suffix
+	if err := m.nsCreator.Create(nms); err != nil {
+		return err
 	}
 	globalConfig, err := m.repoIO.ReadConfig()
 	if err != nil {
@@ -85,9 +80,7 @@
 		Global: globalConfig.Values,
 		Values: derivedValues,
 	}
-	if len(namespaces) > 0 {
-		derived.Release.Namespace = namespaces[0]
-	}
+	derived.Release.Namespace = nms
 	fmt.Printf("%+v\n", derived)
 	err = m.repoIO.InstallApp(
 		app,