Delete query ... should honour cascading delete if defined

[rbygrave]

Unit cases added by PR #1445

Steps to reproduce

Deleting OtoUser ... should cascade delete to OtoUserOptional due to the cascade ALL on the relationship.

The cascade should happen with both delete a bean and delete by query.

@Entity
@Table(name = "oto_user_model")
public class OtoUser extends BaseModel {

  String name;
  
  @OneToOne(optional = true, cascade = CascadeType.ALL)
  OtoUserOptional userOptional;

OtoUser someUser = new OtoUser("someUser");
OtoUserOptional userPref = new OtoUserOptional(...);
...

Ebean.find(OtoUser.class)
  .where() ...
  .delete();

// should delete the associated OtoUserOptional