Update Ecosystem Engineering Team Members entries

Why is this change being made?

In anticipation of Ecosystem becoming a Stage, !86129 (merged), we update the team members departments and role:

• Ecosystem:Integrations in the role, and the following departments:
  • Ecosystem BE Team => Ecosystem:Integrations BE Team (Alex, Andy, Arturo, Luke, Markus)
  • Ecosystem FE Team => Ecosystem:Integrations FE Team (Arturo, Justin, Tom)
• Ecosystem:Contributor Experience in the role, and the following department:
  • new Ecosystem:Contributor Experience Team (Ash, Eipi)
• Ecosystem:Foundations in the role, and the following department:
  • new Ecosystem:Foundations Team (Eipi, Mike)

Author Checklist

• Provided a concise title for the 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 change to the correct DRI(s)
  • 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 in 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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