Simplify evaluation function signatures with keyword arguments

[irhete]

The signatures of our evaluation functions are largely overlapping, in particular when it comes to bootstrapping-related parameters. When changing one of these parameters (e.g. adding another bootstrapping-related param), the current implementation requires one to change the signatures of all of the evaluation functions manually. To reduce this duplication work, we could lump the bootstrapping-related parameters together as bootstrap_kwargs, e.g. eval_function(arg1, arg2, **bootstrap_kwargs).