feat: Add configurable auto logout on inactivity

Users can pick an inactivity timeout in their preferences. A warning
appears 30 seconds before, and activity or a logout is synchronised
across open tabs.

client/src/entry-actions/core.js

@@ -33,9 +33,15 @@ const logout = (revokeAccessToken = true) => ({
   },
 });
 
+const dismissAutoLogoutWarning = () => ({
+  type: EntryActionTypes.AUTO_LOGOUT_WARNING_DISMISS,
+  payload: {},
+});
+
 export default {
   toggleFavorites,
   toggleEditMode,
   updateHomeView,
   logout,
+  dismissAutoLogoutWarning,
 };