Change "lang" to "languageCode" in gql query args

This is to keep the nomenclature consistent across the public api

modules/core/api/product/product.api.graphql

@@ -1,6 +1,6 @@
 type Query {
-    products(lang: LanguageCode): [Product]
-    product(id: Int!, lang: LanguageCode): Product
+    products(languageCode: LanguageCode): [Product]
+    product(id: Int!, languageCode: LanguageCode): Product
 }
 
 type Mutation {

modules/core/api/product/product.resolver.ts

@@ -10,12 +10,12 @@ export class ProductResolver {
 
     @Query('products')
     products(obj, args): Promise<Product[]> {
-        return this.productService.findAll(args.lang);
+        return this.productService.findAll(args.languageCode);
     }
 
     @Query('product')
     product(obj, args): Promise<Product | undefined> {
-        return this.productService.findOne(args.id, args.lang);
+        return this.productService.findOne(args.id, args.languageCode);
     }
 
     @Mutation()
@@ -38,7 +38,3 @@ export class ProductResolver {
         return this.productService.update(input);
     }
 }
-
-export interface MutationInput<T> {
-    input: T;
-}

modules/core/app.module.ts

@@ -6,12 +6,14 @@ import { AdministratorResolver } from './api/administrator/administrator.resolve
 import { AuthController } from './api/auth/auth.controller';
 import { CustomerController } from './api/customer/customer.controller';
 import { CustomerResolver } from './api/customer/customer.resolver';
+import { ProductOptionResolver } from './api/product-option/product-option.resolver';
 import { ProductResolver } from './api/product/product.resolver';
 import { AuthService } from './auth/auth.service';
 import { JwtStrategy } from './auth/jwt.strategy';
 import { PasswordService } from './auth/password.service';
 import { AdministratorService } from './service/administrator.service';
 import { CustomerService } from './service/customer.service';
+import { ProductOptionService } from './service/product-option.service';
 import { ProductVariantService } from './service/product-variant.service';
 import { ProductService } from './service/product.service';
 
@@ -40,6 +42,8 @@ import { ProductService } from './service/product.service';
         CustomerService,
         CustomerResolver,
         ProductService,
+        ProductOptionResolver,
+        ProductOptionService,
         ProductVariantService,
         ProductResolver,
         PasswordService,