Write rukpak cleanup RFC and bring through review

[tmshort]

Write an RFC for rukpak cleanup.

This effort goes in sync with making Rukpak as a library. It involves investigation required to de-duplicate the code between operator-controller and rukpak. Some of the changes could be:

1. Removing the need of controller.
2. Slimming down the unpacker and BD API based on our needs.
3. Investigating if Rukpak can be removed and all the required code can be moved to operator-controller.

Acceptance Criteria:

1. Create a RFC for review illustrating the changes/impact required in Rukpak.

Note - No code changes would be made.

[tmshort]

See https://docs.google.com/document/d/1HCMaD0iwvLAGxfHgPi7JG3RM-jfHOPOSJrJ8Gu_qolI/edit for RFC