Fix domain hiding logic (#7765)

* Send rejections to followers when user hides domain they're on

* Use account domain blocks for "authorized followers" action

Replace soft-blocking (block & unblock) behaviour with follow rejection

* Split sync and async work of account domain blocking

Do not create domain block when removing followers by domain, that
is probably unexpected from the user's perspective.

* Adjust confirmation message for domain block

* yarn manage:translations

app/services/after_block_domain_from_account_service.rb

@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+class AfterBlockDomainFromAccountService < BaseService
+  # This service does not create an AccountDomainBlock record,
+  # it's meant to be called after such a record has been created
+  # synchronously, to "clean up"
+  def call(account, domain)
+    @account = account
+    @domain  = domain
+
+    reject_existing_followers!
+    reject_pending_follow_requests!
+  end
+
+  private
+
+  def reject_existing_followers!
+    @account.passive_relationships.where(account: Account.where(domain: @domain)).includes(:account).find_each do |follow|
+      reject_follow!(follow)
+    end
+  end
+
+  def reject_pending_follow_requests!
+    FollowRequest.where(target_account: @account).where(account: Account.where(domain: @domain)).includes(:account).find_each do |follow_request|
+      reject_follow!(follow_request)
+    end
+  end
+
+  def reject_follow!(follow)
+    follow.destroy
+
+    return unless follow.account.activitypub?
+
+    json = Oj.dump(ActivityPub::LinkedDataSignature.new(ActiveModelSerializers::SerializableResource.new(
+      follow,
+      serializer: ActivityPub::RejectFollowSerializer,
+      adapter: ActivityPub::Adapter
+    ).as_json).sign!(@account))
+
+    ActivityPub::DeliveryWorker.perform_async(json, @account.id, follow.account.inbox_url)
+  end
+end