Restructure hooks to use a hook manager rather than directly hooking

[idmontie]

From @poiuyqwert:

What really needs to be added to GPTP is a centralized hook manager, so that more than one plugin can use the same hooks without interfering. The general concept is that when a user goes to make a hook to their function through the hook manager, instead of adding the hook to that function, it would add the function pointer into an array and actually hook to a function on the manager which would call all the functions in that array.

[idmontie]

There has been some discussion on the best way to do this and how we can best integrate with FireGraft.

The best guess so far is to create a HookManager class similar to this:

class HookManager {
  private:
    HashMap<uint32, LinkedList<void*> functionMap;

 public:
   void addHook(uint32 address, void* callback) {
      functionMap->get(address)->add(callback);
   }

   void attachHooks() {
     // foreach entry in functionMap
     // - attach to address, a function that when called will just run all of the callbacks in the linked list in order.
   }
}