Optimization for boolean questions

[sileix]

the booleanExpression in the boolean questions is currently not optimized. E..g, in the case when it's statically true/false, we could simply use [true]/[false] to avoid the computation, or even avoid running the query entirely.

[gcampax]

Yeah you'll want to add the filter optimization right away because it also normalizes the filters and sorts it by parameter name, which you need for training.