Change log for CITRIX_NETSCALER

Date Changes
2022-06-09 Enhancement- Added requested mappings:
-Mapped 'startTime', 'endTime', 'Duration' to 'security_result.detection_fields'.
-Updated the parser to parse the logs containing message_type - 'CHANNEL_UPDATE', 'NETWORK_UPDATE', 'AAATM Message'.
2022-05-09 Bug-fix - Updated the parser to correctly parse the logs containing message_type - 'TCPCONNSTAT'.
-Updated the grok to include the full domain name in 'principal.administrative_domain'.
-Parsed the logs failing during Validation API testing.
2022-04-27 Enhancement- Added requested mappings
-Mapped intermediary.hostname field
-Parsed Api failed logs