sidekiq-scheduler jobs

Resolves #2495

* 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

* Remove best_in_place

* Replace best_in_place usage with rails helpers

* Move admin/settings#index to #edit action

* Remove click_to__edit from i18n

* downgrade rubocop 0.48.1 => 0.46.0

* exclude vendor/**/* from rubocop target files

* add frozen_string_literal comment line

* fix percent literal delimited by ( and )

* fix alignment

* remove comment disabling unknown cop

Follow-up to #2599. When a domain block with `reject_media` is
added or `rake mastodon:media:remove_remote` is invoked, mastodon
deletes the locally cached attachments and avatars but does not
reflect that change in the database, causing the `file` fields to
still have values. This change persists the deletion in the
database and sets the attachment type to unknown.

This also introduces a one-off rake task that sets all attachments
without a local file to the "unknown" type. The upgrade notes for
the next release should contain a post-upgrade step with
`rake mastodon:media:set_unknown`.

* Adds logging for daily tasks.

* Fixes Code Climate issues in #2438.

* Remove unused method #set_counters_maps from api controller

* Remove unused method #set_account_counters_maps from api controller

* Remove unused method Account#followers_domains

* Remove unused User.prolific scope

* Add mastodon:users:admins task to list all admin emails

* Use interpolated query style in Account.triadic_closures

* Coverage for Account.triadic_closures

Also improve efficiency of the mastodon:maintenance:add_static_avatars task

* Unite all mandatory rake tasks in mastodon:daily
Add mastodon:media:remove_remote task
Make mastodon:maintenance:add_static_avatars more resilient to exceptions

* Fix typo in task description

Before it cleared out user records only (e-mail, password) without
freeing up the associated username (account record). Furthermore, since
these records have no dependent records (due to no user activity)
they can be deleted quickly with delete_all instead of destroy

* Add tasks for open/close registration

* Code climate style fix

* Use true instead of string 'true'

* add task in order to delete unconfirmed user

* change 7 days to 2

* When avatar/header are GIF, generate static versions.
Account API returns "avatar"/"avatar_static", "header"/"header_static"
Static version is the same as original for other cases
Web UI de-animates avatars in toots, lists of users

Fix #441, fix #596, prerequisite for #1064

* Fix JS test

* Add rake task to generate static avatars/headers from GIF ones, add test

* Adds task to confirm user by email.

* Adds documentation for manual confirmation.

redis-backed "mentions" timeline as redundant (given notifications)

(without avatar). Also improved search position of exact matches

to the API

respect hub.lease_seconds (fix #46)