Improve ADO projects staging with single repository

Overview

At the moment when we run congregate stage-projects projectID and there is only one repository in ADO's group (which during listing mapped to GitLab Project without parent namespace / subgroup).

Example:

[
    {
        "id": "1674c12f-e86f-4d6f-8993-98fe7a8a0ea8",
        "name": "bridgecrewio-terragoat",
        "namespace": "hello-world-project",
        "path": "bridgecrewio-terragoat",
        "path_with_namespace": "hello-world-project",
        "visibility": "private",
        "description": "",
        "jobs_enabled": null,
        "packages_enabled": null,
        "project_type": "group",
        "members": [
            {
                "email": "john.doe@gitlabpsoutlook.onmicrosoft.com",
                "id": "aad.ZTlkMzM1NjgtZTZmMi03ZGVhLWI4ZmQtMzA4MzlmYjA2ODhm",
                "name": "John Doe",
                "state": "active",
                "username": "john.doe"
            },
            {
                "email": "adam.bijman@gitlabpsoutlook.onmicrosoft.com",
                "id": "aad.NmEwOTg0ZWItYjI4Yy03YjVjLWJjZWItZTMwOTU3ZWQ2YTg4",
                "name": "Adam Bijman",
                "state": "active",
                "username": "adam.bijman"
            },
            {
                "email": "gitlab-ps@outlook.com",
                "id": "aad.NzE0YzVlNTItMmU1OC03ODgwLWEzMGQtMmZiYjE2ODdjZTk1",
                "name": "GitLab PS",
                "state": "active",
                "username": "gitlab.ps"
            },
            {
                "email": "paul.van.windmill@gitlabpsoutlook.onmicrosoft.com",
                "id": "aad.OTcwYTMwODktNTZjMC03ZmRiLWI1MDItYzIwZWVjM2Y1ZTM4",
                "name": "Paul van Windmill",
                "state": "active",
                "username": "paul.van.windmill"
            }
        ],
        "http_url_to_repo": "https://gitlab-ps@dev.azure.com/gitlab-ps/Hello%20World%20Project/_git/bridgecrewio-terragoat",
        "project_id": "d53abdc7-836e-4fd3-bc89-173d6c4a3108"
    }
]

Such staged project does not have correct namespace and path_with_namespace.

Suggestion:

When we try to stage project that was originally single repository in ADO project we prepend namespace placeholder, like this:

...
"namespace": "<replace-this-with-valid-target-namespace>",
"path": "bridgecrewio-terragoat",
"path_with_namespace": "<replace-this-with-valid-target-namespace>/hello-world-project",
...

Tasks

• Update docs if needed (workflow, runbooks, README, migration metrics, etc.)

Acceptance Criteria

• Existing UTs pass locally
• 100% code coverage on new code

@gitlab-org/professional-services-automation/tools/migration