🚀 Add MR GitLab on the leaderboard

[jeanphi-baconnais]

Let's go to integrate MR GitLab on the oss.zenika.com (issue #311 ).

Steps :

• 1️⃣ add a template of new hacktoberfest.json ✅
• 2️⃣ as the structure of the hactoberfest.json evolved, changes have to be done

[jeanphi-baconnais]

⚠️ After merging this PR, modifications on GCP have to do : copy source code form hactkoberfest-new to hactkoberfest, and remove hactkoberfest-new function.