Use action cable postgres adapter in production

This switches cable environments staging and production to postgresql adapter. No DB change is needed for that as it uses Postgres Notify/Listen and no tables.

ActionCable sends full payload (e.g. Comment body) so there is an issue because Postgres has a hard limit to 8000 bytes: https://www.postgresql.org/docs/13/sql-notify.html. When using NotificationChannel, there's an error when submitting a comment which has more than 8000 bytes (including metadata, mentionings etc)