Refactors the incubation engineering job families

Why is this change being made?

Please see: https://gitlab.com/gitlab-org/incubation-engineering/meta/-/issues/23

Currently, the job roles for incubation engineering are within the engineering folder, from an ownership and availability perspective, this doesn't accurately reflect the organisation structure. This MR is intended to provide ownership of incubation engineering job families to the incubation engineering team as well as identify that these roles are specific to this department.

No changes to role requirements are being made in this MR.

What changes are being made here?

• Creates an incubation-engineering folder under the engineering folder
• Moves incubation-engineer folder into this folder
• Moves VP Incubation Engineering to this folder
  Adds CODEOWNER entries for this subfolder

Author Checklist

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