reduceResultsDT / getJobTable: meta info on cols

[berndbischl]

it be nice to have more grouping info on cols available. that helps with later structuring / aggregating in analysis and should be easy to provide.

groups = char vecs of col names

potential groups

• problem: id + all pars
• algo: id + all pars
• result / outcome: collected outcomes

i could come up with some more for the rest, but these are most useful. especially as these are dynamically defined by the user. the rest are known constants and created by bt all the time.

how could they be returned:

attributes of result. not the biggest fan of this. but might be ok here. could also provide some simple getters.

[berndbischl]

michel, you coded exactly the same principle for BE and called it getResultVars.

https://github.com/tudo-r/BatchExperiments/blob/master/R/reduceResultsExperiments.R