refactor: stack func to client, mv app to new file

Stack interaction is now under client.

App types and functions moved from env to app under config

config/app_test.go

@@ -0,0 +1,37 @@
+package config
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestNewApp(t *testing.T) {
+	app, err := newApp(expectedAppEnv, appName, expectedAppFile)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !reflect.DeepEqual(app, expectedApp) {
+		t.Fatalf("did not get expected app type. Expected: %s; Got: %s", app, expectedApp)
+	}
+}
+
+func TestReadAppEnvFile(t *testing.T) {
+	app, err := readAppEnvFile(expectedAppFile, appName)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !reflect.DeepEqual(app, expectedApp) {
+		t.Fatalf("did not get expected app type. Expected: %s; Got: %s", app, expectedApp)
+	}
+}
+
+func TestGetApp(t *testing.T) {
+	// TODO: Test failures as well as successes
+	app, err := GetApp(expectedAppFiles, appName)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !reflect.DeepEqual(app, expectedApp) {
+		t.Fatalf("did not get expected app type. Expected: %s; Got: %s", app, expectedApp)
+	}
+}