2.3.1

Feature/trainee import (#43)

* install package

* language & detector & wrapper

* dictionnary en & fr

* trainingCourses translation

* Requester translation

* OrgaUnits translation

* navigation menu translation

* modify requester & add i18n

* fix i18n

* enchance

* add icon on navigation menu

* Ui & i18n translate

* fix typo error

* remove aucun label disponible

* fix css

* bump version to 2.3.1