Add /core-team page

What does this MR do and why?

Migrates the /core-team page from www-gitlab-com to the contributor platform.

Few notes:

1. Single data file.
2. Replaced Twitter with X.
3. Images are now pulled from GitLab and hard-coded in data files. We could fetch, but I feel like that's just unnecessary work.
4. I will follow-up with a redirect once this page is migration.

Closes: https://gitlab.com/gitlab-com/marketing/digital-experience/about-gitlab-com/-/work_items/1702

Validation steps

/cc @leetickett-gitlab