Ideas for enhancing TRestDataSet

[jgalan]

Recently, TRestDataSet has been implemented at #345. Cool!

There are few enhancements that can still be interesting, or necessary!

• The file selection using metadata rules might be really time consuming. We should have a FileSelection method that extracts metadata information from a metadata database that has been populated using the ROOT/REST official data repository. Using the restSQL tool. We could have simply an option to decide to use the "SQL" database inside TRestDataSet, or even better, create a new class TRestSQLDataSet::TRestDataSet (inheriting from TRestDataSet) that overloads FileSelection and defines the additional data members required to connect to the SQL database.

• Include cuts on events so that if one of the branches or columns could be used as discriminant to generate a final table of selected events.

• Update the way cuts are introduced inside TRestDataSet so that we can use TRestCut. #388

• Add a method that allows to cut-off events that do not fulfil certain conditions, and at the same time should reduce the fTotalDuration, it could be a method such as TRestDataSet::RemoveDataUnderConditions( std::string ). Adding time correction in dataset generation #443

• Add unit tests / validation pipeline.

See also issue #13