OGM_14,OGM-15,OGM-21 EntityManger#createQuery and createNamedQuery

https://hibernate.atlassian.net/browse/OGM-14
https://hibernate.atlassian.net/browse/OGM-15
https://hibernate.atlassian.net/browse/OGM-21

I started implementing the createQuery method but then I've see the opportunity to playe with the other issues as well.

@emmanuelbernard, could yuo take a look at this?

I'm not sure about the LockOptions but it there were many NullPointerException wihtout adding some support for it.

I've also reused the OgmNativeQuery , I've initially thought this method was only for native queries but it can actually be used for JPA query as well. Should we change the name?