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

Conflicts:
	Dockerfile
	app/javascript/packs/common.js
	config/webpack/loaders/sass.js
	config/webpack/shared.js
	db/schema.rb
	package.json
	yarn.lock

A lot of the conflicts come from updating webpack.

Even though upstream deleted app/javascript/packs/common.js, I kept
glitch-soc's version as it unifies JS/CSS packs behavior across flavours.

Ported glitch changes to webpack 4.x

config/routes.rb

@@ -134,6 +134,13 @@ Rails.application.routes.draw do
     resource :settings, only: [:edit, :update]
     resources :invites, only: [:index, :create, :destroy]
 
+    resources :relays, only: [:index, :new, :create, :destroy] do
+      member do
+        post :enable
+        post :disable
+      end
+    end
+
     resources :instances, only: [:index] do
       collection do
         post :resubscribe