Spike: Research alternative for CentOS 8 packages

Problem Statement

CentOS 8 is EOL on December 31st, 2021: https://www.centos.org/centos-linux-eol/.

The replacement is CentOS Stream, however it is not a direct replacement to CentOS 8: https://itsfoss.com/centos-stream-faq/. In response, a number of alternatives distributions have been launched, as in AlmaLinux and Rocky Linux.

Given the community fragmentation of CentOS and upcoming EOL, GitLab needs to align on a path forward for our official CentOS support.

Solution

This research spike is to discover the best possible alternative.

Outcome

1. Users will be able to install AlmaLinux with SELinux support thanks to this commit gitlab-org/omnibus-gitlab!5714 (merged) that happened during the %14.5 release cycle
2. Distribution selected AlmaLinux to replace CentOS in the builders

See #954 (comment 730198505) for context.