Change domain blocks to automatically support subdomains (#11138)

* Change domain blocks to automatically support subdomains

If a more authoritative domain is blocked (example.com), then the
same block will be applied to a subdomain (foo.example.com)

* Match subdomains of existing accounts when blocking/unblocking domains

* Improve code style

app/services/unblock_domain_service.rb

@@ -14,7 +14,8 @@ class UnblockDomainService < BaseService
   end
 
   def blocked_accounts
-    scope = Account.where(domain: domain_block.domain)
+    scope = Account.by_domain_and_subdomains(domain_block.domain)
+
     if domain_block.silence?
       scope.where(silenced_at: @domain_block.created_at)
     else