Refactor accesses from outside of the Firestarter class

[marenz2569]

Currently we support one instance of the Firestarter class. Variables that need to be accessed from outside the class, e.g. in the sigterm handler are inline static:

  inline static std::unique_ptr<optimizer::OptimizerWorker> Optimizer;
  inline static bool WatchdogTerminate = false;
  inline static std::condition_variable WatchdogTerminateAlert;
  inline static std::mutex WatchdogTerminateMutex;
  inline static volatile LoadThreadWorkType LoadVar = LoadThreadWorkType::LoadLow;

DoD

• Provide an interface to control the runtime adjustable parameters (e.g. termination signal, load status)
• Use a pointer to the Firestarter class to call the functions for adjusting parameters instead of using inline static