Singletons => Change method to make singleton class

NodeApp/src/commander/CommanderCommand.ts

NodeApp/src/commander/enonce/EnonceCommand.ts

NodeApp/src/commander/enonce/EnonceCreateCommand.ts

NodeApp/src/commander/exercice/ExerciceCommand.ts

NodeApp/src/commander/exercice/ExerciceCreateCommand.ts

NodeApp/src/commander/session/App/SessionAppCommand.ts

NodeApp/src/commander/session/App/SessionAppLoginCommand.ts

NodeApp/src/commander/session/App/SessionAppLogoutCommand.ts

NodeApp/src/commander/session/Gitlab/SessionGitlabCommand.ts

...src/commander/session/Gitlab/SessionGitlabLoginCommand.ts

...rc/commander/session/Gitlab/SessionGitlabLogoutCommand.ts

NodeApp/src/commander/session/SessionCommand.ts

NodeApp/src/commander/session/SessionTestCommand.ts

NodeApp/src/config/Config.ts

NodeApp/src/config/LocalConfig.ts

NodeApp/src/managers/DojoBackendManager.ts

NodeApp/src/managers/GitlabManager.ts

NodeApp/src/managers/HttpManager.ts

NodeApp/src/managers/SessionManager.ts

NodeApp/src/shared