Add method to actually create the job based on the template
BUGFIX : refspec not considered when copying a job for a new branch
BUGFIX : use the branches configured on the template
Allow prepare_scm_from to keep branches from original job
Reuse prepare_scm_from on from_template method
Add a configuration hash for pattern/job_template pairs
Iterate over the templates hash if not project is found
BUGFIX : protect against already instantiated templates
BUGFIX : trailing comma left behind ...
BUGFIX : use repo url on payload for template instantiation
BUGFIX : search templates only for unknown repositories

When the git repo is known but not triggered, it should be avoided to
go through the template based job creation.
Last resort template search based on the repository group