Support ADO pipelines with multiple repos

## Description

Azure DevOps pipelines include support for multiple repos in one pipeline. By default ADO pipelines retrieve the same repo the pipeline yaml lives in, but if you want to specify additional repos you can do this inside the YML file.

ADO docs: https://learn.microsoft.com/en-us/azure/devops/pipelines/repos/multi-repo-checkout?view=azure-devops

In order to support re-wiring these additional repos in GEI we'd have to inspect and modify the pipeline YAML file as part of the migration process.

This would involve making at least one commit to the git repo. And the question remains of which branch do we make this commit against?