[FEM] add missing material cards to CMakeLists.txt

[donovaly]

This fixes issue 1. reported here: https://forum.freecadweb.org/viewtopic.php?f=18&t=56912#p489666

[berndhahnebach]

AFAIR: we added not all cards to the rolling dev version. But at the release all cards should be available without this commit. There have been discussion on the forum.

@sgrogan

[donovaly]

AFAIR: we added not all cards to the rolling dev version. But at the release all cards should be available without this commit.

Yes, the are i the release, but most FEM users use the rolling release, for example to benefit from the latest Gmsh features.

I don't see why a few small textfiles should not appear in the rolling releases. When you simulate the different steel material cards are very valuable.