Refactoring - save directly in store

[Tronix117]

Instead of adding included to output object, so that JSData know where to dispatch them, it is safer and cleaner to only add foreignKeys links, and save all included objects directly in each corresponding stores.

It is subject to discussions, but it can further enhance stability, if any issue were to occur.

The drawback is that it needs to be saved in datastore, can't be bypass; however I don't see a use case where you need to fetch included data and don't want to be in datastore (except with raw). So if there is the option to not save in store, then included should be discarded.

This needs more thought and inputs.