Implement criticality search with feedback in Cardinal #1158
Description
Reason
Perform a search for a critical configuration that includes multiphysics feedbacks.
Design
In general, this will combine #1156 and #1157 to invoke OpenMC multiple times in a search for a critical configuration. One key design decision is how often to perform a multiphysics simulation between OpenMC simulations. This could be a user-configurable parameter and might depend on the relative runtime of the multiphysics update vs the OpenMC simulation and/or the possibility for oscillations in the search because of the impact of multiphysics on the search process.