Shared cloud sandbox environment for the Package team

Why is this change being made?

While implementing Create shared test environment in Cloud Sandbox (gitlab-org/container-registry#674 - closed) the Package team became a user of the HackyStack platform. This MR increases the visibility of the usefulness of this platform that allows setup-and-destroy prepared environments seamlessly.

This MR also deprecates the risk mapping section as the team no longer uses it.

Author Checklist

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• Added a description to this MR explaining the reasons for the proposed change, per say why, not just what
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