[customer API] Poll EWT after x seconds / minutes

When a task is enqueued in MRE, MRE will send EWT and task position in queue to Customer API. Customer API should have a configurable x time and it should ask MRE via Chat Server for EWT and Task Position in Queue after every x time.

Request EWT from MRE:

API: <fqdn>/api/EWT?SkillGroup=<SkillGroup>&ConversationId=<conversation-id>&TaskId=<task-id>

Response from MRE:

{
"ConversationId":"<conversation-id>",
"EWT":"<time-in-seconds>",
"TaskId":"<task-id>",
"Position":"<task-position-in-queue>",
"QueueName":"<queue-name-in-which-task-is-enqueued>"
}