sidekiq-scheduler jobs

Resolves #2495

* Add spec for precompute feed service

* Refactor PrecomputeFeedService

* spec wip

* Add specs for the after remote follow workers

* Refactor the after remote follow workers

* Do not cancel PuSH subscriptions after encountering "permanent" error response

After talking with MMN about it, turns out some servers/php setups do
return 4xx errors while rebooting, so this anti-feature that was meant
to take load off of the hub is doing more harm than good in terms of
breaking subscriptions

* Update delivery_worker.rb

* Framework for delivery worker spec

* Refactor of pubsub delivery worker

* Add specs for valid challenge response from pubsub confirmation worker

* Refactor the pubsub confirmation worker

* Spec for feed insert worker when missing records

* more specs!

* Refactor feed insert worker

to all subscribers. IDN-normalize callback URLs for subscriptions on insert.

* add content-type in pubsubhubhub request header

* fix type

* Fix Scheduler::SubscriptionsScheduler, add worker test for it

* Change production log level of Sidekiq to "warn" instead of "info"

* Fix #2473 - Use sidekiq scheduler to refresh PuSH subscriptions instead of cron

Fix an issue where / in domain would raise exception in TagManager#normalize_domain

PuSH subscriptions refresh done in a round-robin way to avoid hammering a single
server's hub in sequence. Correct handling of failures/retries through Sidekiq (see
also #2613). Optimize Account#with_followers scope. Also, since subscriptions
are now delegated to Sidekiq jobs, an uncaught exception will not stop the entire
refreshing operation halfway through

Fix #2702 - Correct user agent header on outgoing http requests

* Add test for SubscribeService

* Extract #expiring_accounts into method

* Make mastodon:push:refresh no-op

* Queues are now defined in sidekiq.yml

* Queues are now in sidekiq.yml

* Fix #2119 - Whenever about to send a HTTP request, normalize the URI

* Add test for IDN request in FetchLinkCardService

* Perform IDN normalization on domains before they are stored in the DB

* Make private toots get PuSHed to subscription URLs that belong to domains where you have approved followers

* Authorized followers controller, stub for bulk action

* Soft block in the background

* Add simple test for new controller

* Rename Settings::FollowersController to Settings::FollowerDomainsController, paginate results,
rename "private" post setting to "followers-only", fix pagination style, improve post privacy
preferences style, improve warning style

* Extract compose form warnings into own container, show warning when posting to followers-only with unlocked account

* Remove trailing whitespace

* Use query methods instead of explicit .blank? checks

* Allow export of mutes list

* Allow importing of mutes list

* Refactor to use Settings::Exports::BaseController and DRY up exports code

* Add spec for settings/imports controller

* Add failing spec for settings/imports#create

* Fix broken imports

* Refactor ImportWorker

* Fix #1141, fix #1126 - Work through UpdateRemoteProfileService for both <feed> and <entry> top-level tags

* Improve code quality, remove line unrelated to fix

* Rewrite Atom generation from stream entries to use Ox instead of Nokogiri::Builder

StreamEntry is now limited to only statuses, which allows some optimization. Removed
extra queries on AccountsController#show. AtomSerializer instead of AtomBuilderHelper
used in AccountsController#show, StreamEntriesController#show, StreamEntryRenderer
and PubSubHubbub::DistributionWorker

PubSubHubbub::DistributionWorker moves n+1 DomainBlock query to PubSubHubbub::DeliveryWorker
instead.

All Salmon slaps that aren't based on StreamEntry still use AtomBuilderHelper and Nokogiri

* All Salmon slaps now use Ox instead of Nokogiri. No touch from status on account

make regeneration worker unique, (only schedule/execute once at a time)

must be added to the Sidekiq invokation in your systemd file

The pull queue will handle link crawling, thread resolving, and OStatus
processing. Such tasks are more likely to hang for a longer time (due to
network requests) so it is more sensible to not make the "in-house" tasks
wait for them.

Allow PuSH to distribute private toots with that condition

if account lock info was up to date, otherwise re-do the FollowService
with now updated information