Update CI/CD JTBDs

Why is this change being made?

To reflect the changes made to groups in Verify/Release/Configure through https://gitlab.com/gitlab-com/Product/-/issues/5470.

This MR includes the following changes:

• Moving Secret Management JTBDs from Pipeline Authoring & Configure ----> Pipeline Security
• Moving Variables JTBDs from Pipeline Authoring ----> Pipeline Security
• Moving Code testing and Review App JTBDs from Pipeline Insights(Security) ----> Pipeline Execution

Author Checklist

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