CI - Complete PR via VSTS CLI

[mathieu-benoit]

https://docs.microsoft.com/en-us/cli/vsts
https://github.com/Microsoft/vsts-cli
https://channel9.msdn.com/Events/Connect/2017/T186

As optional for the CI lab:

• vsts code pr list
• vsts code pr policies list --id
• vsts code pr update --delete-source-branch on
• vsts code pr complete --id