Send heardbeat from ui to back

[freddidierRTE]

In certain circumstances , the network is cut between the browser and the cards-consultation services but the connection does not close on the back , this situation has been observe in production for a duration of 1 hour . So the user is considered connected where as it is not the case

Solution :
Send every X minutes an HTTP heartbeat request from the UI to the back . The endpoint shall cards/CardSubscriptionHeartBeat

If the back did not receive the heartbeat for Y minutes , it closes the connection

By default X = 60s
and Y = 150 s

Implementation :

• Add a last connection date in services/cards-consultation/src/main/java/org/opfab/cards/consultation/services/CardSubscription.java
• Update it when receiving hearbeat
• Add a new Thread in services/cards-consultation/src/main/java/org/opfab/cards/consultation/services/CardSubscriptionService.java