Lists (#5703)

* Add structure for lists

* Add list timeline streaming API

* Add list APIs, bind list-account relation to follow relation

* Add API for adding/removing accounts from lists

* Add pagination to lists API

* Add pagination to list accounts API

* Adjust scopes for new APIs

- Creating and modifying lists merely requires "write" scope
- Fetching information about lists merely requires "read" scope

* Add test for wrong user context on list timeline

* Clean up tests

app/models/stream_entry.rb

@@ -3,13 +3,13 @@
 #
 # Table name: stream_entries
 #
-#  activity_id   :bigint
+#  id            :integer          not null, primary key
+#  activity_id   :integer
 #  activity_type :string
 #  created_at    :datetime         not null
 #  updated_at    :datetime         not null
 #  hidden        :boolean          default(FALSE), not null
-#  account_id    :bigint
-#  id            :bigint           not null, primary key
+#  account_id    :integer
 #
 
 class StreamEntry < ApplicationRecord