Allows a user to request both quantity and age conditions be met prior to build discard.
This means that if N max builds are set with M max age, builds will only be cleared if they exceed
the given age and if their quantity exceed the N max build quantity. The feature will thus never
allow build deletion to leave less builds than the N max builds set, or allow build deletion of builds
under the M max age regardless of N max builds set.
NOTE: This feature does nothing if Days to keep builds and/or Max # of builds to keep are empty.