* Replace env module with process.env.NODE_ENV

* Refactor i18n module

* Remove pluralization

* Fix i18n imports

* Normalize locale strings

* Fix wrong dialog title

* Remove unused strings

* Change i18n string interpolation

* Update i18n keys

* Move empty menu to menus module

* Add i18next

* Allow asynchronous initialization of i18n

* Refactor i18n initialization

* Deactivate i18n initialization in test mode