Add logout button

.env

.env.dev

src/App.js

src/auth/actions/Logout.js

src/auth/pages/logoutPage/LogoutPage.js

src/auth/pages/redirectPage/RedirectPage.js

src/auth/reducers/index.js

src/auth/routes/index.js

src/common/components/CERNToolBar/CERNToolBar.js

src/common/reducers/SnackbarReducer.js