add Apollo Client subscription to ui-control

[rtang03]

after the authentication to done on ui-control, for each query request. #81 #77 #85

We then implement authenticated subscription upon Event Arrival.

[rtang03]

Revisiting the Apollo documentation, it recommends to use subscription (websocket), for low-latency requirement.

BTW, the current requirement will get notification, after commit is made successfully. And, it is better to use long-poll.

Therefore, I make use of Redis, to store the event arrival information, with redis keys to starting with "noti::"

The UI-control, will use periodically poll to obtain this notification information from Redis.

Also, the first time, the client fetch the notification information in Redis, it will make "READ".

The backend websocket remains live, for future use. For example, B2B integration, which requires low-latency communication.