PDI direction and capacity updates

Why is this change being made?

Direction page

The Product Data Insights direction page has a lot of unnecessary content that quickly goes out of date. This MR simplifies and page and makes it easier/more obvious to navigate to our main handbook to engage with the team

PDI handbook

There are a few updates

1. New framework for analyst capacity should be added to handbook
2. New section-priority:: labels should be added to handbook
3. The office hours content was excessive and not truly applicable (it was written before we knew what office hours would look like). This MR reduces and simplifies the content to make it more approachable and easier to understand

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, 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
• 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.

---