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/locales/simple_form.en.yml

@@ -13,6 +13,7 @@ en:
           other: <span class="name-counter">%{count}</span> characters left
         fields: You can have up to 4 items displayed as a table on your profile
         header: PNG, GIF or JPG. At most 2MB. Will be downscaled to 700x335px
+        inbox_url: Copy the URL from the frontpage of the relay you want to use
         irreversible: Filtered toots will disappear irreversibly, even if filter is later removed
         locale: The language of the user interface, e-mails and push notifications
         locked: Requires you to manually approve followers
@@ -52,6 +53,7 @@ en:
         expires_in: Expire after
         fields: Profile metadata
         header: Header
+        inbox_url: URL of the relay inbox
         irreversible: Drop instead of hide
         locale: Interface language
         locked: Lock account