Delete all repos in a project

As a migrator, I want to quickly delete all repos in a project so that I can re-run a migration

As a devops, I want to delete a repo from PowerShell as part of some other project related automation, for example, to move repos from one project to another and eliminate possibility of committing to the wrong place and not noticing

Notes: easy to commit to different repos, so on the surface not a big deal, but is an issue if there are a large number of repositories and if user is not checking remotes

Start with the repository's existing PowerShell scripts and Azure DevOps project/repository operations; the issue does not name a file, command entry point, or test. Define the supported deletion scope and safeguards for deleting all repositories or one repository, then verify the behavior against a migration or automation scenario.

Written by the indexing model from the issue text.