Match the selected SOP classes of StoragePresentationContexts to DCMTK

[medihack]

As mentioned in #977, pynetdicom currently uses other selected SOP classes in StoragePresentationContexts than DCMTK. In my opinion (and also from a radiologist's point of view), the DCMTK selection is a bit more appropriate (this is, of course, debatable).

This is what DCMTK uses
And this is what pynetdicom

If there is some interest, I can create a PR that matches the StoragePresentationContexts with that of DCMTK.

[scaramallion]

Sounds good to me