Mark an Organization / Top-Level Group as Isolated
## Problem Statement
We are working towards isolating an Organization at the Rails level (see [parent epic](https://gitlab.com/groups/gitlab-org/-/epics/19414)). This means that we should be confident that any write operations against this Organization should not cross organizational boundaries, otherwise we've broken the isolation model, which jeopardises transfers/promotions of top-level groups to Organizations.
For this epic, we need to define a process to determine whether an Organization (or top-level group) is an **isolated** data graph within the database, and reliably measure this status.
## Exit criteria
* We are able to measure the data graph of a given top-level group or Organization and capture all its relationships
* By crawling this graph, we are able to determine whether or not the entity spans more than a single Organization in relations
* Based on this output, we are able to confidently assert whether or not an Organization is fully isolated
## DRI
@alexpooley
epic