Update Product Division OKR workflow to include UX and latest revisions

Why is this change being made?

Related to issue https://gitlab.com/gitlab-com/www-gitlab-com/-/issues/13957

Related to MR (supporting templates) Product!641 (merged)

Due to UX joining the Product Division and other updates to company OKR workflow and tools, the Product OKR guidance page needs to be updated. This MR aligns the page to represent the latest FY23 Q4 workflow. Overall structure/timeline/participants will hold through Fy24 Q1 onward, however specifics of tools/scoring will change once the GitLab OKR MVC is release in FY24 Q1.

Please note my goal is to keep this workflow really light in this MR, unlike the past. The issue templates will have more detailed guidance, rather than putting a ton of guidance on the page. Especially because we're in transition and tools are shifting from Ally to GitLab in Q1.

Author Checklist

• 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.
• 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
• If the changes affect team members, or warrant an announcement in another way, please consider posting an update in #whats-happening-at-gitlab linking to this MR
  • If this is a change that directly impacts the majority of global team members, it should be a candidate for #company-fyi. Please work with internal communications and check the handbook for examples.

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