Enhanced handling of XS requests

[FDS: https://intranet.genesys.com/pages/viewpage.action?spaceKey=RDSIPS&title=%5BFDS%5D+Enhance+handling+of+error+responses+from+FS+dial+plan]

SIP Server will be enabled to handle different HTTP error responses from Feature Server for Dial Plan requests, in appropriate way to notify the origination.

Also, any extended service (XS) request will get timed out after a set timeout value and the request will be rejected by SIP Server.

Switchover SIP Server to backup mode, when there is no active connection to any of the configured Feature Server URLs.