instantiate Data should be part of the data objects

[schalkdaniel]

We should move the instantiate data function to the data objects since each base-learner now has its own data container. This keeps the code in one place and does not require to copy the code between base-learner and factories ...

[schalkdaniel]

This is already solved by instantiating the data into the data container, the base learner re-uses the data.