The variables CI_PARAM_IMAGE, CI_PARAM_DISTRO, CI_MACHINE have been
defined outside the job in the '.gitlab-ci.yml' file. This has a lower
precedence then variables defined inside the job, but it seems that
these variables are used in the scope of 'Trigger variables' when
available in the trigger job. These override the value set in the
template. As main results this made FNGSystem jobs build the normal
yocto.

* Move all build, deploy and test stubs to the manifest-build.yml
* Create a new job to generate and trigger the build jobs dynamically
* Add the base jinja2 file for the build jobs.
* Add initial docs for the manifest pipeline
* Remove unused files