It seems there is no plugin to display a project list of your gitlab, so do this
Step 1) Install this plugin
Step 2) Generate a access token in your gitlab https://docs.gitlab.com/ce/user/profile/personal_access_tokens.html
Step 3) Paste the token in to line 4 below
Step 4) Paste the these code https://gitlab.com/snippets/1686114 into your page
Step 5) For the gitlab restful api reference, read this https://docs.gitlab.com/ce/api/projects.html
Finally you will see this: