Hello Harshal!
Currently there's no action pack for siebel, bu a feature request has already been placed.
We have managed the complete build, versioning and deployment within a short development time using the existing action packs. Quite simple and straighforward. It's running now for about a year. Next steps will be continuous delivery and zero downtime.
Last open issue is that siebel does not offer a way how to activate TaskUI flows from outside the application. This is still a manual step.
Kind regards,
Adam