Change algo3 to add the ID factor automatically

[allpan3]

Currently, whenever switching to algo3, we have to modify the FACTORS and CODEVECTORS configs to account for the extra ID factor. We should be able to let the dataset class do it.
Note we should not change VSA class to account for algo since algo is not an attribute of VSA. The only place we can do this is the dataset class.
A better solution may be extending the VSA class for algo3, like how we do it in the multi-concept-MNIST project. Let's see if we can get around it without doing so first.