feat!: Upgrade backend (Python, Django, Wagtail)

[mgax]

⚠️ After deploying this change, the following command should be run on the production instance, to copy daily search hits data from the wagtailsearch.Query model to wagtailsearchpromotions.Query:

./manage.py copy_daily_hits_from_wagtailsearch

---

Upgrade the backend across the board:

• Fix deprecation warnings (moved to chore: Fix warnings #352)
  • Move bibliography app config to apps.py
  • Replace url with re_path
  • Replace usage of deprecated assertEquals
  • Treat warnings as testing errors
• Switch to pip-tools version pinning
• Upgrade to Django 4.0
  • Add workaround for missing source maps (needs further investigation) Fix source map output in webpack
• Drop django-compressor and django-libsass (they don't seem to do anything useful; the frontend build already compiles *.scss files)
• Upgrade to Wagtail 4.2
• Upgrade to Django 4.1
• Upgrade to Python 3.11
• Write test for a simple search query (because search broke when upgrading to Wagtail 5.0)
• Upgrade to Wagtail 5.0
  • Update the search views to match the current reference implementation.
  • Remove partial_match for index fields. Search is using the database backend which doesn't support partial matches anyway.
  • Check if slugs are still being generated in the admin.
• Django 4.2
• Wagtail 5.1 (fixes Update to Wagtail 5.1 #322)
• Wagtail 5.2
• Python 3.12
• Other Python dependencies
• Frontend upgrades (moved to chore: Frontend upgrade #354)
  • Check for unmaintained frontend dependencies
  • Node 18
  • Node 20

[mgax]

Since Django 4.0, ManifestStaticFilesStorage checks for missing files, and the build output with inline-source-map was failing because of a link to a missing bootstrap.esm.js.map. Changing the devtool option to eval-source-map, which is their Recommended choice for development builds with high quality SourceMaps, fixed the issue