Upgrade to latest redis-rb 4.x and fix deprecations (#23616)

Gemfile.lock

app/lib/feed_manager.rb

app/models/follow_recommendation_suppression.rb

app/services/batched_remove_status_service.rb

app/workers/scheduler/follow_recommendations_scheduler.rb

config/environments/development.rb

config/environments/test.rb

config/initializers/redis.rb

db/migrate/20170920032311_fix_reblogs_in_feeds.rb

db/migrate/20200407202420_migrate_unavailable_inboxes.rb

lib/mastodon/feeds_cli.rb