Add firefox education landing page (Fixes #15953)

[alexgibson]

One-line summary

Add UK influencer campaign phase 2 page (education).

Significant changes and points to review

This is a greatly simplified version of the /firefox/new/ page with updated copy and imagery. The original CSS was pretty complex, so I tried to simplify it by replacing some of the custom layouts with standard protocol layouts (which I'm guessing didn't exist at that time). An extra pair of eyes to check that there's nothing else left in that's no longer needed would be appreciated.

Issue / Bugzilla link

#15920

Testing

http://localhost:8000/en-GB/firefox/landing/education/

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.57%. Comparing base (5bdebe7) to head (9f0d2e3).
Report is 96 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #15967   +/-   ##
=======================================
  Coverage   79.57%   79.57%           
=======================================
  Files         160      160           
  Lines        8396     8396           
=======================================
  Hits         6681     6681           
  Misses       1715     1715           

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[alexgibson]

Closing as this is stale