Secure planning

Why is this change being made?

This is a revamp of https://handbook.gitlab.com/handbook/engineering/development/sec/secure/workflow/.

The last content update was about 2 years ago, and informal feedback from engineers was generally that they didn't know this page existed.

My personal perspective is that we no longer follow some of what's currently documented, which goes against our handbook principles.

Changes:

• Include a planning overview, not just refinement.
• Move page to https://handbook.gitlab.com/handbook/engineering/development/sec/secure/planning/.
• Remove and simplify content.
• Update content to match reality.

In making these edits, I followed these guiding principles:

• Less is more. Engineers want a quick guide for how to perform tasks, and not a textbook explaining the minutia of every decision.
• Don't be overly prescriptive. Teams have different needs, so mandating rules that are not efficient for everyone makes the guidelines less effective.

I reused/copied some of the work that @lkerr and I created for https://handbook.gitlab.com/handbook/engineering/development/sec/security-risk-management/srm-planning/. While this creates some duplication, I intend to propose that we move content that overlaps across the section to https://handbook.gitlab.com/handbook/engineering/development/sec/, at which point we'd have a SSOT.

Author and Reviewer Checklist

Please verify the check list and ensure to tick them off before the MR is merged.

• Provided a concise title for this Merge Request (MR)
• Added a description to this MR explaining the reasons for the proposed change, per say why, not just what
  • Copy/paste the Slack conversation to document it for later, or upload screenshots. Verify that no confidential data is added, and the content is SAFE
• Assign reviewers for this MR to the correct Directly Responsible Individual/s (DRI)
  • If the DRI for the page/s being updated isn’t immediately clear, then assign it to one of the people listed in the Maintained by section on the page being edited
  • If your manager does not have merge rights, please ask someone to merge it AFTER it has been approved by your manager in #mr-buddies
  • The when to get approval handbook section explains the workflow in more detail
• For transparency, share this MR with the audience that will be impacted.
  • Team: For changes that affect your direct team, share in your group Slack channel
  • Department: If the update affects your department, share the MR in your department Slack channel
  • Division: If the update affects your division, share the MR in your division Slack channel
  • Company: If the update affects all (or the majority of) GitLab team members, post an update in #whats-happening-at-gitlab linking to this MR
    • For high-priority company-wide announcements work with the internal communications team to post the update in #company-fyi and align on a plan to circulate in additional channels like the "While You Were Iterating" Newsletter