[ADF-1548] deprecate the usage of the "forRoot" methods in modules (#2344)

* remove CoreModule.forRoot

* remove forRoot methods

* fix form issues (lint)

ng2-components/ng2-alfresco-viewer/index.ts

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-import { ModuleWithProviders, NgModule } from '@angular/core';
+import { NgModule } from '@angular/core';
 import { CoreModule } from 'ng2-alfresco-core';
 
 import { MaterialModule } from './src/material.module';
@@ -63,22 +63,11 @@ export const VIEWER_DIRECTIVES: any[] = [
         ViewerService
     ],
     exports: [
+        MaterialModule,
         ...VIEWER_DIRECTIVES
     ],
     entryComponents: [
         ViewerDialogComponent
     ]
 })
-export class ViewerModule {
-    /** @deprecated in 1.8.0 */
-    static forRoot(): ModuleWithProviders {
-        console.log('ViewerModule.forRoot is deprecated and will be removed in future versions');
-        return {
-            ngModule: ViewerModule,
-            providers: [
-                RenderingQueueServices,
-                ViewerService
-            ]
-        };
-    }
-}
+export class ViewerModule {}

ng2-components/ng2-alfresco-viewer/src/directives/extension-viewer.directive.spec.ts

@@ -35,7 +35,7 @@ describe('ExtensionViewerComponent', () => {
 
     beforeEach(async(() => {
         TestBed.configureTestingModule({
-            imports: [CoreModule.forRoot()],
+            imports: [CoreModule],
             providers: [
                 ExtensionViewerDirective,
                 {provide: ElementRef, useClass: MockElementRef},