Differentiate between solver settings files in the solid mechanics example

[davidrudlstorfer]

Thanks again for the very nice tutorial with all the explanations - this was really helpful and gave very nice insights!

One thing we struggled with (admittedly very dumb from us) was that the solver files within the solid_mechanics tutorial were available twice. They are once contained in solid_mechanics/and in solid_mechanics/weak_scaling_comparison. We made changes to the wrong file and were always wondering why the results didn't change.

Maybe it would be helpful to differentiate between those solver files in the name (add _weak_scaling or something at the end). Or even reuse them if possible based on only slight differences or no differences at all (for example the ILU file).

Feel free to just close the issue if it is not helpful