Adjustments to the CPS support chain check
Initial (accidental) commit did not have full functionality. This fleshes out the check_CPS function, such that it matches all support chains, extracts their L1 items, and then searches to determine if all the seeded supports from each L1 item are in a CPS group.
Some further discussion needed to understand if this should be enforced (with limited exceptions) via CI test, or if the script should only be run as a periodic check.