Bot nameplates (#7391)

* Store actor type in database

* Add bot nameplate to web UI, add setting to preferences, API, AP
Fix #7365

* Fix code style issues

app/models/account.rb

@@ -45,6 +45,7 @@
 #  moved_to_account_id     :bigint(8)
 #  featured_collection_url :string
 #  fields                  :jsonb
+#  actor_type              :string
 #
 
 class Account < ApplicationRecord
@@ -149,6 +150,16 @@ class Account < ApplicationRecord
     moved_to_account_id.present?
   end
 
+  def bot?
+    %w(Application Service).include? actor_type
+  end
+
+  alias bot bot?
+
+  def bot=(val)
+    self.actor_type = ActiveModel::Type::Boolean.new.cast(val) ? 'Service' : 'Person'
+  end
+
   def acct
     local? ? username : "#{username}@#{domain}"
   end