Add scifi decoding test
I added a branch to the conditions DB with the ReadoutMap for bank versions 4, 5 and 6. Using that branch should allow samples produced with bank version 6 to be decoded with DD4HEP. I think for versions 4 and 5 the geometry was different (61 vs 64?).
See this branch in lhcb-conditions-database.
FYI: @sponce