SCM integration workflows.yml format

File should be named workflows.yml. Other variations like workflow.yaml aren't supported

For now we are supporting the following schema:

workflow: # the name of the workflow. A regular string
  steps: # list of steps
    - branch_package: # the name of the step. It is defined by the OBS. Today just branch_package is supported
        source_project: home:Admin # OBS project
        source_package: hello_world # OBS package