Validation Framework: Max distance also when no LUT is used

[wpreimes]

It seems that the lut_max_dist keyword is currently only used when a lookup table is calculated (as the name suggests). When reading data in the data manager is done from a NN search (using the coords directly without calculating a LUT first) it seems that there is no possibility to limit the search distance at the moment (it has to be done when creating the joblist).

We should implement this and make the max_lut_dist keyword more general (to work in both cases, when a LUT is calculated and when reading from coords directly).