Merge branch 'master' into glitch-soc/merge-upstream

Conflicts:
- app/controllers/settings/follower_domains_controller.rb
  Removed upstream. Did the same here. Maybe we should not have?
- config/locales/en.yml
  Upstream removed the “Authorized followers” page and associated
  translations. This is too close in the file to our glitch-soc-specific
  “flavour” string. No actual conflict.
- config/locales/ja.yml
  Same as above.
- config/locales/pl.yml
  Same as above.
- config/navigation.rb
  No real conflict. New route added too close to the glitch-soc-specific
  “flavours” one.
- config/webpack/configuration.js
  Upstream refactored the webpack(er) configuration quite a bit.
  Tried to keep up.
- config/webpack/loaders/babel.js
  Upstream refactored the webpack(er) configuration quite a bit.
  Tried to keep up.
  The contents of this file have been moved to package.json.
- config/webpack/shared.js
  Upstream refactored the webpack(er) configuration quite a bit.
  Tried to keep up.
- config/webpacker.yml
  Upstream refactored the webpack(er) configuration quite a bit.
  Tried to keep up.
- jest.config.js
  The contents of this file have been moved to package.json.
- package.json
  Upstream refactored the webpack(er) configuration quite a bit.
  Tried to keep up.
- yarn.lock
  Upstream refactored the webpack(er) configuration quite a bit.
  Tried to keep up.

app/views/layouts/mailer.html.haml

@@ -24,7 +24,7 @@
                               %tr
                                 %td.column-cell
                                   = link_to root_url do
-                                    = image_tag full_pack_url('logo_full.png'), alt: 'Mastodon', height: 34, class: 'logo'
+                                    = image_tag full_pack_url('media/images/mailer/logo_full.png'), alt: 'Mastodon', height: 34, class: 'logo'
 
     = yield
 
@@ -49,4 +49,4 @@
                                 %p= link_to t('application_mailer.notification_preferences'), settings_notifications_url
                               %td.column-cell.text-right
                                 = link_to root_url do
-                                  = image_tag full_pack_url('logo_transparent.png'), alt: 'Mastodon', height: 24
+                                  = image_tag full_pack_url('media/images/mailer/logo_transparent.png'), alt: 'Mastodon', height: 24