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

Conflicts:
- `README.md`:
  Upstream added a link to the roadmap, but we have a completely different README.
  Kept ours.
- `app/models/media_attachment.rb`:
  Upstream upped media attachment limits.
  Updated the default according to upstream's.
- `db/migrate/20180831171112_create_bookmarks.rb`:
  Upstream changed the migration compatibility level.
  Did so too.
- `config/initializers/content_security_policy.rb`:
  Upstream refactored this file but we have a different version.
  Kept our version.
- `app/controllers/settings/preferences_controller.rb`:
  Upstream completely refactored user settings storage, and glitch-soc has a
  different set of settings.
  The file does not directly references individual settings anymore.
  Applied upstream changes.
- `app/lib/user_settings_decorator.rb`:
  Upstream completely refactored user settings storage, and glitch-soc has a
  different set of settings.
  The file got removed entirely.
  Removed it as well.
- `app/models/user.rb`:
  Upstream completely refactored user settings storage, and glitch-soc has a
  different set of settings.
  References to individual settings have been removed from the file.
  Removed them as well.
- `app/views/settings/preferences/appearance/show.html.haml`:
  Upstream completely refactored user settings storage, and glitch-soc has a
  different set of settings.
  Applied upstream's changes and ported ours back.
- `app/views/settings/preferences/notifications/show.html.haml`:
  Upstream completely refactored user settings storage, and glitch-soc has a
  different set of settings.
  Applied upstream's changes and ported ours back.
- `app/views/settings/preferences/other/show.html.haml`:
  Upstream completely refactored user settings storage, and glitch-soc has a
  different set of settings.
  Applied upstream's changes and ported ours back.
- `config/settings.yml`:
  Upstream completely refactored user settings storage, and glitch-soc has a
  different set of settings.
  In particular, upstream removed user-specific and unused settings.
  Did the same in glitch-soc.
- `spec/controllers/application_controller_spec.rb`:
  Conflicts due to glitch-soc's theming system.
  Mostly kept our version, as upstream messed up the tests.

app/workers/poll_expiration_notify_worker.rb

@@ -3,7 +3,7 @@
 class PollExpirationNotifyWorker
   include Sidekiq::Worker
 
-  sidekiq_options lock: :until_executed
+  sidekiq_options lock: :until_executing
 
   def perform(poll_id)
     @poll = Poll.find(poll_id)

app/workers/scheduler/indexing_scheduler.rb

@@ -6,17 +6,21 @@ class Scheduler::IndexingScheduler
 
   sidekiq_options retry: 0
 
+  IMPORT_BATCH_SIZE = 1000
+  SCAN_BATCH_SIZE = 10 * IMPORT_BATCH_SIZE
+
   def perform
     return unless Chewy.enabled?
 
     indexes.each do |type|
       with_redis do |redis|
-        ids = redis.smembers("chewy:queue:#{type.name}")
-
-        type.import!(ids)
-
-        redis.pipelined do |pipeline|
-          ids.each { |id| pipeline.srem("chewy:queue:#{type.name}", id) }
+        redis.sscan_each("chewy:queue:#{type.name}", count: SCAN_BATCH_SIZE) do |ids|
+          redis.pipelined do
+            ids.each_slice(IMPORT_BATCH_SIZE) do |slice_ids|
+              type.import!(slice_ids)
+              redis.srem("chewy:queue:#{type.name}", slice_ids)
+            end
+          end
         end
       end
     end