GET /sessions is missing status information

[maheshc01]

GET /sessions api call is missing a status field in its response body which would be used to indicate the current status of the qos session. This would be a very valuable piece of information for the developer and needs to be incorporated.

[SyeddR]

This issue is for GET /sessions/{sessionId}

Following values can be considered for session status

• active: session has been established and active
  -pending_active : session request has been accepted and in the process of establishment
• delete: session has been deleted
• pending delete: session request has been accepted and in the process of deletion
• failed: network has failed to established the session

We probably also need to match the status in notification api. And include description as well

[jlurien]

This is related with the discussions for PR #67
A session life cycle and their possible states should be agreed for that.

[hdamker]

Closed with merge of PR #67