[AAE-5660] Reduce SCSS mixins and use CSS variables instead (#2255)

* optimise create menu theme

* optimise details component

* optimise sidenav component

* optimise search input theme

* optimise template dialog theme

src/app/components/create-menu/create-menu.component.ts

@@ -34,6 +34,7 @@ import { AppExtensionService } from '@alfresco/aca-shared';
 @Component({
   selector: 'app-create-menu',
   templateUrl: './create-menu.component.html',
+  styleUrls: ['./create-menu.component.scss'],
   encapsulation: ViewEncapsulation.None,
   host: { class: 'app-create-menu' }
 })