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

Conflicts:
- `Gemfile.lock`:
  Not a real conflict, just a glitch-soc-only dependency too close to a
  dependency that got updated upstream. Updated as well.
- `app/models/status.rb`:
  Not a real conflict, just a change too close to glitch-soc-changed code
  for optionally showing boosts in public timelines.
  Applied upstream changes.
- `app/views/layouts/application.html.haml`:
  Upstream a new, static CSS file, conflict due to glitch-soc's theming
  system, include the file regardless of the theme.
- `config/initializers/content_security_policy.rb`:
  Upstream dropped 'unsafe-inline' from the 'style-src' directive, but
  both files are very different. Removed 'unsafe-inline' as well.

app/serializers/oembed_serializer.rb

@@ -4,7 +4,7 @@ class OEmbedSerializer < ActiveModel::Serializer
   include RoutingHelper
   include ActionView::Helpers::TagHelper
 
-  attributes :type, :version, :title, :author_name,
+  attributes :type, :version, :author_name,
              :author_url, :provider_name, :provider_url,
              :cache_age, :html, :width, :height
 

app/serializers/rss/account_serializer.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class RSS::AccountSerializer
+class RSS::AccountSerializer < RSS::Serializer
   include ActionView::Helpers::NumberHelper
   include AccountsHelper
   include RoutingHelper
@@ -17,18 +17,7 @@ class RSS::AccountSerializer
     builder.image(full_asset_url(account.avatar.url(:original))) if account.avatar?
     builder.cover(full_asset_url(account.header.url(:original))) if account.header?
 
-    statuses.each do |status|
-      builder.item do |item|
-        item.title(status.title)
-            .link(ActivityPub::TagManager.instance.url_for(status))
-            .pub_date(status.created_at)
-            .description(status.spoiler_text.presence || Formatter.instance.format(status, inline_poll_options: true).to_str)
-
-        status.media_attachments.each do |media|
-          item.enclosure(full_asset_url(media.file.url(:original, false)), media.file.content_type, media.file.size)
-        end
-      end
-    end
+    render_statuses(builder, statuses)
 
     builder.to_xml
   end

app/serializers/rss/tag_serializer.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class RSS::TagSerializer
+class RSS::TagSerializer < RSS::Serializer
   include ActionView::Helpers::NumberHelper
   include ActionView::Helpers::SanitizeHelper
   include RoutingHelper
@@ -14,18 +14,7 @@ class RSS::TagSerializer
            .logo(full_pack_url('media/images/logo.svg'))
            .accent_color('2b90d9')
 
-    statuses.each do |status|
-      builder.item do |item|
-        item.title(status.title)
-            .link(ActivityPub::TagManager.instance.url_for(status))
-            .pub_date(status.created_at)
-            .description(status.spoiler_text.presence || Formatter.instance.format(status).to_str)
-
-        status.media_attachments.each do |media|
-          item.enclosure(full_asset_url(media.file.url(:original, false)), media.file.content_type, media.file.size)
-        end
-      end
-    end
+    render_statuses(builder, statuses)
 
     builder.to_xml
   end