(1) Converted that config option (in vspExperimental) into an enum with `minOfDurationAndEndTime' (default,
old behavior), `endTimeOnly' and `tryEndTimeThanDuration'.
(2) Adapted the time mutator by pulling the standard PlanMutateTimeAllocation apart into two classes,
where a `simplified' version is now called with the (new, non-default) simpler duration interpretations.
(3) Those very few places where the new duration interpretation was used will get results that are not bit-compatible to previous results. This is due to the simplified time mutation that makes fewer assumptions.