[CI] Move test parameters to some kind of config file

[hageboeck]

For those variables it could be nice to get them out of the source and into some "config file", maybe also make a distinction between CPU and GPU execution? It's fine for me to create an issue for that and merge as such though.

Originally posted by @roiser in #109 (comment)

[valassi]

This is more a comment on the original #109 than on this one. As discussed in #72 note that the reproducibility of the test results (ie the validity of the reference file) depends on some parameters which may change over time and over configurations. In particular I changed neppR from 4 to 8 and this made the test fail as the reference is now invalid. The good side is that now this neppR=8 is hardcoded and no longer linked to single/double precision or to AVX capabilities, so hopefully the reference can remain the same. But it would be useful to keep this in mind.

[roiser]

for the gridpack generation I have added now variables into the run_card.dat file which are the consumed by the python infrastructure when building the code.