Fix welcome message action + Show the main menu  + Keyhanlder optimisation
Fix welcome message action + Show the main menu  + Keyhanlder optimisation

lsaffre/lino_extjs6,lsaffre/lino_extjs6,lino-framework/extjs6,lino-framework/extjs6,lsaffre/lino_extjs6,lsaffre/lino_extjs6,lino-framework/extjs6,lsaffre/lino_extjs6