Removal of project listing

[plouc]

Listing projects from this tool doesn't seem to make sense, we sometimes have hundreds of projects and GitLab API only support a max of 100 items per page, as it targets CI and doesn't allow user input, maybe this feature should be removed.

For a more complex CLI to interact with GitLab, we can use something like glc, se https://github.com/plouc/go-gitlab-client#glc-list-projects, it supports interactive mode with pagination, search…