GitLab integration, new message if commit after an approval, ...

✨ New

• new notification in channel if someone pushed new commits in an already approved PR,
• release of the GitLab integration and updated our onbaording accordingly
• possibility to change the number of reviewers maximum to invite while inviting a team as a reviewer on GitHub (default: 4)

🔨 Improvements

• do not archive a team-specific channel if it was not created by Axolo
• added a warning in the Axolo home if the engineer is not fully onboarded
• ability to prevent engineers from onboarding by themselves on the Axolo home
• using the engineer's GitHub oAuth to delete comments in GitHub

🐞 Fixes

• PR reminders were not working for incomplete engineers' Slack profiles
• incoming webhook optimization