Add Adam as Omar's trainee maintainer mentor

Description

@OmarQunsulGitlab is working to become a database maintainer #14098 (closed), but he will benefit from the help of a database maintainer mentor. @ahegyi was his onboarding buddy when he joined GitLab and is happy to help him with the maintainership.

I will let you both organize a coffee chat and discuss the mentor/mentee relationship. Thanks!

cc. @blabuschagne as Adam's manager.

Reference: https://about.gitlab.com/handbook/engineering/workflow/code-review/#reviewer-mentorship-program