* Remove obsolete search plugins and related patches and default settings.
  These were added to upstream's Ubuntu distribution configuration
  (https://bugzilla.mozilla.org/show_bug.cgi?id=1651330).
  - debian/install-distribution-searchplugins.py
  - debian/searchplugins/*.xml
  - debian/config/searchplugins.conf
  - debian/patches/no-region-overrides-for-google-search.patch
  - debian/patches/partially-revert-google-search-update.patch
* Update packaging scripts accordingly
  - debian/distribution.ini
  - debian/firefox.{dirs,install,links}.in
  - debian/rules
* Update patches
  - debian/patches/rust-drop-dll-checksums.patch