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.

Gemfile

@@ -15,7 +15,7 @@ gem 'makara', '~> 0.4'
 gem 'pghero', '~> 2.2'
 gem 'dotenv-rails', '~> 2.7'
 
-gem 'aws-sdk-s3', '~> 1.31', require: false
+gem 'aws-sdk-s3', '~> 1.32', require: false
 gem 'fog-core', '<= 2.1.0'
 gem 'fog-openstack', '~> 0.3', require: false
 gem 'paperclip', '~> 6.0'
@@ -87,7 +87,7 @@ gem 'tty-command', '~> 0.8', require: false
 gem 'tty-prompt', '~> 0.18', require: false
 gem 'twitter-text', '~> 1.14'
 gem 'tzinfo-data', '~> 1.2018'
-gem 'webpacker', '~> 3.5'
+gem 'webpacker', '~> 4.0'
 gem 'webpush'
 
 gem 'json-ld', '~> 3.0'