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

Conflicts:
- `Gemfile.lock`:
  No real conflict, glitch-soc-only dependency (redcarpet) too close to an
  upstream one (rdf-normalize)
- `README.md`:
  we have different READMEs, discarded upstream's changes
- `app/views/admin/custom_emojis/index.html.haml`:
  No real conflict, different context because of glitch-soc theming
- `lib/mastodon/statuses_cli.rb`:
  Upstream added code to keep bookmarked statuses, we were already doing so
  with slightly different code. Discarded upstream's changes.
- `package.json`:
  No real conflict, glitch-soc-only dependency (favico.js) too close to
  an upstream one

app/models/account.rb

@@ -316,10 +316,6 @@ class Account < ApplicationRecord
     self.fields = tmp
   end
 
-  def subscription(webhook_url)
-    @subscription ||= OStatus2::Subscription.new(remote_url, secret: secret, webhook: webhook_url, hub: hub_url)
-  end
-
   def save_with_optional_media!
     save!
   rescue ActiveRecord::RecordInvalid