core package extraction

What does this MR do?

This MR is based on !831 (merged) and aim to extract a core package to be used for building gitlab-runner-helper

Why was this MR needed?

Are there points in the code the reviewer needs to double check?

Does this MR meet the acceptance criteria?

• Documentation created/updated
• Tests
  • Added for this feature/bug
  • All builds are passing
• Branch has no merge conflicts with master (if you do - rebase it please)

What are the relevant issue numbers?