Allow custom new record behaviour

[mpscholten]

if I order blog posts by title, how can I ensure they maintain the order when a new item is added to the internal store via subscriptions? (by @jokull)

We should have a way to override the detectNewRecordBehaviour logic.

https://github.com/digitallyinduced/ihp/blob/master/lib/IHP/DataSync/ihp-datasync.js#L235