Tech evaluation for initial GitLab Releaser implementation

Based on discussion here gitlab#199253 (comment 278527929)

The purpose of this issue is to get a better understanding of the complexity for the new gitlab-releaser tool defined in the issue gitlab#199253 (closed)

The idea would be to have a rough implementatio/PoC as defined in the handbook. The following functionality should be implemented

• Add the command gitlab-releaser create and support -name and -description
• Implement the POST /projects/:id/releases endpoint of the Release API https://docs.gitlab.com/ee/api/releases/#create-a-release
• Add some unit tests
• Simple build pipeline