Create report for tracked private projects

To support maintenance and oversight of these tracked private projects, we will need to make a report to view this information without having to directly connect to the database. The data returned would be CSV plain text with headers. This way we could easily copy and paste the outputs into a spreadsheet if needed for shared work.

The URL I'm thinking that builds on existing (or soon to be existing) endpoints is /git/webhooks/gitlab/reports, where we can add different reports based on webhook data. Some of these filters would include deleted private projects, private projects without forks, and the like. This data would be exclusively what's in the database, rather than data that lives in Gitlab. While this data should ideally be the same, there may be cases where it's not.

@mbarbero for initial reports/filters, I'm thinking of the following for useful starting points:

• All tracked private projects
• Active private projects
• Private projects without parent repo
• Deleted private projects (for usage stats)

Are there any other reports you think would be useful?