Add People section - PersonIndexPage and PersonPage

[Pra26nav]

Closes #567, part of #566

What this adds

• PersonIndexPage model with intro field
• PersonPage model with first_name, last_name, role,
  department, bio, photo, email, linkedin_url fields
• Templates for both pages
• WagtailPageTestCase tests alongside
• generate_people management command (faker)
  for generating 50-100 realistic people pages

Still to come

• Expanding to 100 people pages
• Press releases section

[thibaudcolas]

👋 please don’t use AI to write contributions like this in the future. See our GSoC AI policy. When this policy isn’t followed, we may resort to a ban from Wagtail community spaces, or automatic disqualification from GSoC participation. It’s clear you haven’t given this enough human input as this has clearly already been implemented in #574.