Allow locking CI runner to project when registering the runner
Currently, to lock a CI runner to a specific project, a user registers the runner by invoking the gitlab-runner from the CI machine with a global or project specific registration token. Then, if this runner needs to be locked to the project to prevent other projects from using it, the user must access the GitLab UI and select a checkbox to enable locking.
Allow locking the CI runner to a specific project when registering the CI runner. The project to lock to would be defined by the registration token.