Add overloads to ISession.Get taking both an entityName and a lockMode

[idiotsky]

ISession.Get methods have no overloads taking both an entityName and a lockMode, which, as a result, forces to lock in a separated query when getting an entity by entity name.

In high concurrency environments, it may cause issues.

Generic Get<T> methods also lack overloads with an entityName argument, which are required when the class is not the entity name.

[fredericDelaporte]

Async methods being generated from sync ones by our development process, it is better to refer to the sync version when asking for changes which are not async specific. So I have edited the request.

I have also reworded it as a feature request.