CI: Create job configs for building the Azure-Jenkins images

[pvandervelde]

We want to bootstrap this thing, i.e. we want the Jenkins instance to build the images for the next version. We'll need:

• Configurations for Jenkins which people can copy
• GIT repository that can be cloned?

[pvandervelde]

When handling GIT jenkins normally works in detached HEAD mode. That works for building code but doesn't work so well for the different tools that interact with GIT. So it is possible to fix that by doing this: http://stackoverflow.com/questions/11511390/jenkins-git-plugin-detached-head/13598493#13598493