Gc azure tests

[abbra]

Based on https://github.com/freeipa/freeipa/compare/master...stanislavlevin:azure_integration_tests, experiment with building multi-container environment for testing GC in Azure Pipelines.

Steps to be done:

• [ ] rebase to Rawhide
• [ ] add Samba AD container
• [ ] establish two-way trust to Samba AD
• [ ] add GC test