refactor(RTL mode): to save developers time from searching docs and Google to prepare RTL mode, optional arguments are set to their default values. Now they just need to change NbLayoutDirection.LTR to NbLayoutDirection.RTL and the theme switchs to RTL mode.

src/app/@theme/theme.module.ts

@@ -12,6 +12,7 @@ import {
   NbSelectModule,
   NbIconModule,
   NbThemeModule,
+  NbLayoutDirection,
 } from '@nebular/theme';
 import { NbEvaIconsModule } from '@nebular/eva-icons';
 import { NbSecurityModule } from '@nebular/security';
@@ -85,6 +86,8 @@ export class ThemeModule {
             name: 'default',
           },
           [ DEFAULT_THEME, COSMIC_THEME, CORPORATE_THEME, DARK_THEME ],
+          null,
+          NbLayoutDirection.LTR,
         ).providers,
       ],
     };