Document Syslog-ng log forwarding to Parseable

[nitisht]

Syslog-ng supports sending logs to http endpoints as per the docs here: https://www.syslog-ng.com/technical-documents/doc/syslog-ng-open-source-edition/3.24/administration-guide/37#TOPIC-1298006

We need to document how to fetch logs in json format and forward logs to Parseable

[sakti]

@nitisht I also want to take this issue.

[nitisht]

Thanks @sakti , moving this to you