FEAT #8805 One file to rule them all

lang/en.json

lang/fr.json

rest/index.php

...app/configuration/controllers/ConfigurationController.php

src/app/user/controllers/UserController.php

src/core/controllers/LangController.php

src/core/lang/lang-en.php

src/core/lang/lang-fr.php

src/frontend/app/app.module.ts

src/frontend/app/profile/profile.component.html