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

Conflicts:
- `app/controllers/api/v1/statuses_controller.rb`:
  Conflict due to upstream adding a new parameter (with_rate_limit),
  too close to glitch-soc's own additional parameter (content_type).
  Added upstream's parameter.
- `app/services/post_status_service.rb`:
  Conflict due to upstream adding a new parameter (rate_limit),
  too close to glitch-soc's own additional parameter (content_type).
  Added upstream's parameter.
- `app/views/settings/preferences/appearance/show.html.haml`:
  Conflict due to us not exposing theme settings here (as we have
  a different flavour/skin menu).
  Took upstream change, while still not exposing theme settings.
- `config/webpack/shared.js`:
  Coding style fixes for a part we have rewritten.
  Discarded upstream changes.

app/controllers/admin/site_uploads_controller.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module Admin
+  class SiteUploadsController < BaseController
+    before_action :set_site_upload
+
+    def destroy
+      authorize :settings, :destroy?
+
+      @site_upload.destroy!
+
+      redirect_to edit_admin_settings_path, notice: I18n.t('admin.site_uploads.destroyed_msg')
+    end
+
+    private
+
+    def set_site_upload
+      @site_upload = SiteUpload.find(params[:id])
+    end
+  end
+end