This issue is about preparing a design document of a top level architecture for the plugins that will be developed in the 'Multibranch Pipeline Support for GitLab' Project.

• Objectives and expectations based on proposal
• Answer questions such as
  • "How is the user going to use this?",
  • "What configurations are needed?", 
  • "What are the components of the plugin?"
• Create diagrams of API
• Write mini user guides as if project is already done

After completion, reality mapping shall be done through a discussion with the key stakeholders in Branch Source Plugins.