pick up from the last change handled by using since

We should record the last-sequence and save it in the trigger DB.
This way if the server goes away (i.e restarted) when it returns and start following changes, it will pick up from the last changes handled.

In the handler where the trigger is fired, also save the changes.last_seq , then use this value if present when starting to follow changes, if not set then use "now"