Geo: SSH push to secondary specs

What does this MR do?

This MR adds QA specs for testing git push to secondary for SSH.

Based off https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/7491

⚠ Needs gitlab-qa!181 (merged) merged in order to succeed as it contains the necessary commands to enable https://docs.gitlab.com/ee/administration/operations/fast_ssh_key_lookup.html which is critical for qa/specs/features/browser_ui/ee_geo/ssh_push_secondary_spec.rb.

What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ee/issues/7516

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?