Rework optimization routines

This PR adds:

• an optimizee abstract type that is used as input by all optimization routines
  • needs to be implemented by user with desired functionality
  • three reference implementations:
    • function_optimizee : simple function optimization taking an array of parameters
    • likelihood_optimizee : likelihood optimization using sigma, stddev and likeli
    • eval_optimizee : optimization using an eval/objective pair (eval_interface, objective_interface)
• a reworked eval interface for eval/objective based optimization
  • only takes config and sim_data
  • sim_data is an array of sim_data_t instances (array should reflect domains in mHM)
  • sim_data_t holds an array of variables that can be 1 to 5 dimensional
• renamed existing optimization modules:
  • mo_optimizee now holds the optimizee abstract type and its reference implementations
  • mo_opt_eval_utils contains the eval/objective interfaces and the definitions for config_t and sim_data_t