Do not register repository classes to dependency injection by default

[hikalkan]

We always use repositories over interfaces (like ICustomerRepository or IRepository<Customer, Guid>). However, if anyone injected the repository class (like CustomerRepository), this will be a breaking change.

To continue to use the old behaviour, write this in the beginning of your application:

AbpRepositoryConventionalRegistrar.ExposeRepositoryClasses = true;

We do this since it improves performance.