* Make "unfollow" undo pending outgoing follow request too

* Add cancel button to web UI when awaiting follow request approval

* Make the hourglass button do the cancelling

* Do not raise unretryable exceptions in ResolveRemoteAccountService

* Removed fatal exceptions from ResolveRemoteAccountService

Exceptions that cannot be retried should not be raised. New exception
class for those that can be retried (Mastodon::UnexpectedResponseError)

* Add status destroy authorization to policy

* Create explicit unreblog status authorization

* Fix nil input not handled well in AuthorExtractor concern

* Fix hard error in ProcessFeedService when replied-to status has been deleted

* Fix nil errors in ProcessInteractionService when favourited status
cannot be found

* Add buttons to block and unblock domain

* Relationship API now returns "domain_blocking" status for accounts,
rename "block entire domain" to "hide entire domain", fix unblocking domain,
do not block notifications from domain-blocked-but-followed people, do
not send Salmons to domain blocked users

* Add test

* Personal domain blocks shouldn't affect Salmon after all, since in this
direction of communication the control is very thin when it comes to
public stuff. Best stay consistent and not affect federation in this way

* Ignore followers and follow request from domain blocked folks,
ensure account domain blocks are not created for empty domain,
and avoid duplicates in validation

* Purge followers when blocking domain (without soft-blocks, since they
are useless here)

* Add tests, fix local timeline being empty when having any domain blocks

* 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 #2196 - Respond with 201 when Salmon accepted, 400 when unverified
Fix #2629 - Correctly handle confirm_domain? for local accounts
Unify rules for extracting author acct from XML, prefer <email>, fall back
to <name> + <uri> (see also #2017, #2172)

* 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

coming in via Salmon.

Currently no way to prevent remote follows, but they will only receive public
and unlisted posts

Fix #233, fix #268

respect hub.lease_seconds (fix #46)

as well as formatting of content