Initial version of Pine SGG homepage

Why is this change being made?

Looks like the Pine home page is still untouched – high time we give it some personality! Luckily Lyle still had all the fun SGG images from a while back.

Besides the image, I've added some details about existing workflows and processes. I want to stress that the idea here is not me dictating things – this page can and should be iterated on! I think I mostly captured what is currently true, but please add review comments if you disagree.

Having these documented properly is helpful for new joiners and existing members alike, and will make it easier to iterate on it going forward.

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.

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