Khatrirao cleanup

[ntjohnson1]

I was looking at our khatrirao implementation and realized it needed a little TLC. This is a small PR:

1. Remove debug prints (could leave them in place a logs at a debug level so they can be turned back on in the future but I assume for now can just prune)
2. Update interface to only take repeated matrices to simplify
3. Add linting and typing to improve our coverage and also to validate everything matches the new interface. Since a lot of our core tensors already have types this immediately pointed out incorrect usages just based on types.
4. We had special cased things based on the value of ncols_first but that doesn't actually look like it is required