Implement Seed to generate a CODEOWNERS file and all associated records
# Why?
While working on https://gitlab.com/gitlab-org/gitlab/-/issues/508172+ I realised it would be a good idea to implement a database seed to test the various supported configurations of CODEOWNERS.
I'm proposing we create a [development seed](https://docs.gitlab.com/development/development_seed_files/) that will create an array of records required to test all valid and invalid configurations and also create a project with multiple branches containing different codeowner files.
We could also create merge requests that demonstrate which owners would be applied
# Proposal
The seed should create a group structure following the findings from https://gitlab.com/gitlab-org/gitlab/-/issues/508172+
issue