*: Switch consumers over to Django 5.2

[kai]

Summary

Django 4.2 reached its End-of-Life on 7th April 2026 and Django 5.2 is
the new LTS (= Long Term Support) release which will be supported until
April 2028.

* Switch most ports that use www/py-django42 to www/py-django52.

* Where necessary, remove PORTSCOUT, which is no longer needed because
  an update to a newer version that no longer supports Django 4.2 should
  now be possible.

* Bump PORTREVISION due dependency change where necessary.

PR:     291707

Test Plan

• poudriere -> OK (14.3-RELEASE amd64)
• As soon as this diff is committed (ETA towards the end of May), the next step is to switch the consumers that are still using the py-dj52-* ports accordingly and deprecate the py-dj52-* ports afterwards.

Note:

• Please ignore devel/py-sortinghat and www/seahub for now. Both ports need to be updated to a newer release, which is more complex, and it is very likely that they will be decoupled from this review in the further process.

[kai]

• Rebase
• Add maintainers from the various ports as reviewers.