[Life] Use PiecewiseConstantHazardDistributions from SurvivalDistributions.jl #13
Description
Once SurvivalDistributions.jl is registered, we should move up the current implementation of the Life random variable to leverage the PiecewiseConstantHazardDistributions that are in SurvivalDistributions.jl to offload the management of the random variable to SurvivalDistributions.jl instead of having it here.