Add personnummer and samordningsnummer to SEBasePractitioner

[vjernelov]

In the private sector in Sweden it's pretty common for practitioners to not have an HSA-id, but instead be identified using personnummer or even samordningsnummer (for instance medical doctors coming in from Norway). This is currently not explicitly expressed in SEBasePractitioner.

Suggested solution is to add additional slices for samordningsnummer and personnummer in parallell to the HSA-id slice.

[vadi2]

See #60