Add new CI predefined variables with version components

What does this MR do?

This MR adds environment varariables to the CI build jobs:

• CI_SERVER_VERSION_MAJOR
• CI_SERVER_VERSION_MINOR
• CI_SERVER_VERSION_PATCH
• CI_SERVER_VERSION_PRERELEASE

What are the relevant issue numbers?

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/46050

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• [ ] Conforms to the database guides
• [ ] EE specific content should be in the top level /ee folder
• For a paid feature, have we considered GitLab.com plans, how it works for groups, and is there a design for promoting it to users who aren't on the correct plan?