feat(module,app): basic module to list apps

pkg/module/app/memory/testdata/app.js

@@ -0,0 +1,17 @@
+var ctx = context.new();
+
+var manifests = app.list(ctx);
+
+if (manifests.length !== 2) {
+    throw new Error("apps.length: expected '2', got '"+manifests.length+"'");
+}
+
+var manifest = app.get(ctx, 'dummy2.arcad.app');
+
+if (!manifest) {
+    throw new Error("manifest should not be null");
+}
+
+if (manifest.id !== "dummy2.arcad.app") {
+    throw new Error("manifest.id: expected 'dummy2.arcad.app', got '"+manifest.id+"'");
+}