Add new Mozilla advertising pages [fix #15198]

[craigcook]

One-line summary

Updates the /advertising page, now a set of pages with more detailed info on specific products. This is meant to go live by 2 October 2024

Issue / Bugzilla link

#15198

Testing

http://localhost:8000/advertising/
http://localhost:8000/advertising/formats/
http://localhost:8000/advertising/principles/

[craigcook]

Marking Do Not Merge because I'm waiting for an updated hero image for the main page, but it should be ready for code review otherwise.

[craigcook]

There's a test failure in the newsletter form which seems unrelated to anything in this PR, not sure what's up with that. Fixed

[craigcook]

Marking Do Not Merge because I'm waiting for an updated hero image for the main page, but it should be ready for code review otherwise.

The image has been updated, this can merge once it passes code review.

[reemhamz]

This was a big PR, and you did a very good job with it!
I left some suggestions and fixes that should be quick to patch up.
I'll approve this for now since it needs to go out soon, so feel free to merge after you work on the changes. r+wc

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.88%. Comparing base (2df9c9b) to head (f2eb8af).
Report is 5 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #15228   +/-   ##
=======================================
  Coverage   77.88%   77.88%           
=======================================
  Files         163      163           
  Lines        8480     8480           
=======================================
  Hits         6605     6605           
  Misses       1875     1875           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.