Remove GameArchives dependency

[Max]

Since LibOrbisPkg can now read and write PKG files on its own, there is no reason to drag along GameArchives. Unfortunately, GameArchives is still a dependency because LibArchiveExplorer is used for the file view GUI in PkgEditor. All that's needed to remove this dependency is a new file view UI that uses the memory-mapped file classes.

This will have the added benefit of also adding parallel extraction to the PkgEditor GUI.