Add RBAC required by the InstaScale controller

[astefanutti]

WHY

Part of the CodeFlare operator re-design, as described in project-codeflare/adr#9.

WHAT

Include the RBAC manifests required by the InstaScale controller, e.g., those required to consume the MachineSet and ClusterVersion APIs.

HOW

Copy the InstaScale RBAC into separate manifests.

To be done on top of #216.

TESTS

Make sure the embedded InstaScale controller works as expected.