Move parse and validation logic to own classes

[vladdeSV]

Currently all parsing and validation is done in each country's parser class. This has caused logic to be spread around the codebase. I believe the code would be much more maintainable (and logical) if logic was contained within each type of national identification number class.

Ex. SwedenNINParser uses static methods in SwedenNIN to validate a checksum.

[vladdeSV]

Note: I know from experience with this library that it will not be an easy task to refactor code in this way, because of the many occurrences of very similar code being used for multiple of a NIN's subclasses (see Sweden and Norway).

I still believe it is in this projects best interest to go this path.

[vladdeSV]

This would make it possible to create a specific type of NIN directly.

Currently the parser assumes the type of the NIN, but if one wishes to specifically create a subset of a country's NINs then they currently cannot do that.