[C++] Investigate reporting filter selectivity for filter order optimization

[asfimport]

If we have highly selective filters we can reduce the total amount of work we need to do if we run those filters first. For example, in TPC-H query 6 we are either casting decimals to doubles and running comparisons or we are performing somewhat costly double comparisons. At the same time we have a highly selective date filter. If we can evaluate that date filter first then we can reduce the amount of decimal arithmetic we need to do.

It's a little unclear to me at the moment how much of this is something we want to back into the execution engine versus how much of this should be getting provided to us by some kind of intelligent runtime optimizing planner.

Reporter: Weston Pace / @westonpace

_{Note: This issue was originally created as ARROW-15522. Please see the migration documentation for further details.}