Merge branch '407-change-standard-desktop-theme-to-light' into 'master'

set standard desktop theme to light theme (arsnova)

Closes #407

See merge request arsnova/frag.jetzt!410

src/app/components/shared/footer/footer.component.ts

@@ -56,8 +56,8 @@ export class FooterComponent implements OnInit {
         this.themeService.activate('dark');
         this.themeClass = 'dark';
       } else {
-        this.themeService.activate('dark');
-        this.themeClass = 'dark';
+        this.themeService.activate('arsnova');
+        this.themeClass = 'arsnova';
       }
     }
     this.styleService.setColor(this.themeService.getThemeByKey(this.themeClass).isDark);