Add DxHttpModule to Angular app template (#894)

* Import DxHttpModule

* Add http module test

---------

Co-authored-by: Rochmar Nicolas (DevExpress) <[email protected]>

Author: tomodasheesh

packages/devextreme-schematics/src/add-layout/index.ts

@@ -181,6 +181,7 @@ function updateAppModule(host: Tree, sourcePath: string) {
   };
 
   const rules = [
+    modifyFileRule(appModulePath, importSetter('DxHttpModule', 'devextreme-angular/http')),
     modifyFileRule(appModulePath, importSetter('SideNavOuterToolbarModule', './layouts')),
     modifyFileRule(appModulePath, importSetter('SideNavInnerToolbarModule', './layouts')),
     modifyFileRule(appModulePath, importSetter('SingleCardModule', './layouts')),

packages/devextreme-schematics/src/add-layout/index_spec.ts

@@ -99,6 +99,7 @@ describe('layout', () => {
     expect(styles[2]).toBe('src/themes/generated/theme.additional.css');
 
     const moduleContent = tree.readContent('/src/app/app.module.ts');
+    expect(moduleContent).toContain('import { DxHttpModule }');
     expect(moduleContent)
       .toContain('import { SideNavOuterToolbarModule, SideNavInnerToolbarModule, SingleCardModule }');
     expect(moduleContent)