Fix most rubocop issues (#2165)

* Run rubocop --autocorrect on app/, config/ and lib/, also manually fix some remaining style issues

* Run rubocop --autocorrect-all on db/

* Run rubocop --autocorrect-all on `spec/` and fix remaining issues

lib/tasks/glitchsoc.rake

@@ -1,8 +1,12 @@
+# frozen_string_literal: true
+
 namespace :glitchsoc do
   desc 'Backfill local-only flag on statuses table'
   task backfill_local_only: :environment do
-    Status.local.where(local_only: nil).find_each do |st|
-      ActiveRecord::Base.logger.silence { st.update_attribute(:local_only, st.marked_local_only?) }
+    Status.local.where(local_only: nil).find_each do |status|
+      ActiveRecord::Base.logger.silence do
+        status.update_attribute(:local_only, status.marked_local_only?) # rubocop:disable Rails/SkipsModelValidations
+      end
     end
   end
 end