Merge Syberia 2 and Syberia II into one entry

[heldderarbeit]

Expected behavior

I think these two games should be fused into one single item, since they are the same thing essentially only with a different title.

There might be additional games with this problem, but I haven't found more of them in my library.

Actual behavior

Steps to reproduce

Own Syberia 2 both on Steam and GOG

Version and environment

elementary OS 0.16.1-ebb46ff-master