Avoiding "*" dimensions in the parameters

Parameters p_gnPolicy(grid, node, param_policy, *) and p_groupPolicy3D(group, param_policy, *) currently use the "*" dimension. This is a bit dangerous because of possible typos in the input files. I think in p_gnPolicy the "*" dimension could be directly replaced by "emission" ($$loaddc commands in 1e_inputs.gms need to be reordered) but p_groupPolicy3D we would maybe need to divide into two parameters: p_groupPolicyEmission for emissions and p_groupPolicyUnit for units. I suppose we should still do that? The "*" dimension in set flowUnit(flow, *) could also be updated.