Fix the phpDoc for moveTopics

Signed-off-by: Shitiz Garg <mail@dragooon.net>
findSearchAPI returns an instance of search_api_interface

Signed-off-by: Shitiz Garg <mail@dragooon.net>
Add callbacks to search API when a post or topic is removed or moved

Signed-off-by: Shitiz Garg <mail@dragooon.net>