Bugfix: Correct FEM edge ordering and orientation

[OttTs]

Fixes FEM output by:

• Ordering element-local edge IDs according to the CGNS convention.
• Adding (correct) orientations in the EdgeInfo array by using signed EdgeIDs.

[kopperp]

Thanks for the fixes. Does it make sense to FEM to some of the analyze.toml, so we can find future regressions?

[OttTs]

Sure, that would be useful. The FEM output is still not fully working even for a structured 3D box, though, so I'm trying to get that sorted first.