Add Inconsistent Policy Simulation

[andrewrosemberg]

• [x] Allow the user to run a different model at the forward pass (simulation step). Similar to what was done in this paper. Original issue in https://github.com/andrewrosemberg/HydroPowerModels.jl/issues/54
• [ ] Add stopping criteria that checks: Average Simulation Stalling and Bound Stalling (this can be done by implementing each criteria separately and combining them as described in SDDP.jl). A version was implemented in:
  • BoundStalling
  • Simulation Stalling convergence.jl.zip