Merge branch 'remove-former-beta-program' into 'master'

Removing GitLab Beta Program documentation

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/148406



Merged-by: Lee Tickett <ltickett@gitlab.com>
Approved-by: Rostyslav Safonov <rsafonov-ext@gitlab.com>
Co-authored-by: Nick Veenhof <nveenhof@gitlab.com>