Better integrate Yocto Baseline into Genivi CI

GDP is quite extensively integrated into the Genivi CI go.cd server. For example all GDP PRs pushed to github are automatically built for all officially supported platforms as a build test.

Although pipelines for the Yocto Baseline exist in the CI the BIT realises it could be integrated more closely to help the team achieve the goal of improving the baseline.

This task has been created to manage that process. Aiming for pragmatic achievable goals, rather than perfection. Further tasks can be added as needed down the line.

The first step is to analyse what additional features we want to add. Some ideas for discussion:
1. extend pipelines to build all of the current three official supported qemu targets: x86, x86_64 and armv7.
2. consider adding aarch64/armv8 to that list. Possibly as a non-graphical target as a first step if necessary.
3. automatic build against official targets for all github PRs.