Allow 3rd party debugging on CI machines

With all commits going through CI, there is the occasional issue with failures that can only be reproduced on CI systems or require a configuration which the contributor does not have access to. In the days when Nokia controlled CI, these could be solved by allowing Nokia employees to SSH into the CI systems (in a QA controlled process, where it was taken out of CI by QA temporarily while it was being used for debugging) which allowed for actually debugging and fixing the problems in the CI environment.

For cases where failures are occurring that trusted 3rd party devs cannot reproduce, for example on hardware they do not possess, there should be a way that the Qt QA team can grant them temporary SSH access to the CI machine which is failing, so they can debug it properly.